Method and apparatus of deriving feedback resource for sidelink transmission in a wireless communication system

ABSTRACT

A method and apparatus are disclosed from the perspective of a first device. In one embodiment, the method includes the first device performs sensing on a data resource pool, and the first device selects/derives at least a first data resource from the data resource pool based on the sensing result of the data resource pool. The method further includes the first device transmits a first control information on a first control resource, wherein the first control information allocates or indicates the first data resource. The method also includes the first device performs a first data transmission on the first data resource to at least one second device. Furthermore, the method includes the first device determines or derives a first set of feedback resource(s) based on the first control resource and/or the first data resource; and the first device receives a first set of feedback transmission(s) on the first set of feedback resource(s) from at least the one second device, wherein the first set of feedback transmissions are associated with the first data transmission.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present Application claims the benefit of U.S. Provisional PatentApplication Ser. No. 62/736,113 filed on Sep. 25, 2018, the entiredisclosure of which is incorporated herein in their entirety byreference.

FIELD

This disclosure generally relates to wireless communication networks,and more particularly, to a method and apparatus of deriving feedbackfor sidelink transmission in a wireless communication system.

BACKGROUND

With the rapid rise in demand for communication of large amounts of datato and from mobile communication devices, traditional mobile voicecommunication networks are evolving into networks that communicate withInternet Protocol (IP) data packets. Such IP data packet communicationcan provide users of mobile communication devices with voice over IP,multimedia, multicast and on-demand communication services.

An exemplary network structure is an Evolved Universal Terrestrial RadioAccess Network (E-UTRAN). The E-UTRAN system can provide high datathroughput in order to realize the above-noted voice over IP andmultimedia services. A new radio technology for the next generation(e.g., 5G) is currently being discussed by the 3GPP standardsorganization. Accordingly, changes to the current body of 3GPP standardare currently being submitted and considered to evolve and finalize the3GPP standard.

SUMMARY

A method and apparatus are disclosed from the perspective of a firstdevice. In one embodiment, the method includes the first device performssensing on a data resource pool, and the first device selects/derives atleast a first data resource from the data resource pool based on thesensing result of the data resource pool. The method further includesthe first device transmits a first control information on a firstcontrol resource, wherein the first control information allocates orindicates the first data resource. The method also includes the firstdevice performs a first data transmission on the first data resource toat least one second device. Furthermore, the method includes the firstdevice determines or derives a first set of feedback resource(s) basedon the first control resource and/or the first data resource; and thefirst device receives a first set of feedback transmission(s) on thefirst set of feedback resource(s) from at least the one second device,wherein the first set of feedback transmissions are associated with thefirst data transmission.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagram of a wireless communication system according toone exemplary embodiment.

FIG. 2 is a block diagram of a transmitter system (also known as accessnetwork) and a receiver system (also known as user equipment or UE)according to one exemplary embodiment.

FIG. 3 is a functional block diagram of a communication system accordingto one exemplary embodiment.

FIG. 4 is a functional block diagram of the program code of FIG. 3according to one exemplary embodiment.

FIG. 5 is a reproduction of FIG. 1 of 3GPP R2-162709.

FIGS. 6 and 7 are reproduction of figures of 3GPP R3-160947.

FIG. 8 shows an exemplary deployment with single TRP cell.

FIG. 9 shows an exemplary deployment with multiple TRP cells.

FIG. 10 shows an exemplary 5G cell comprising a 5G node with multipleTRPs.

FIG. 11 an exemplary comparison between a LTE cell and a NR cell.

FIG. 12 is a diagram according to one exemplary embodiment.

FIG. 13 is a reproduction of Table 14.2-2 of 3GPP TS 36.212 V15.2.1.

FIG. 14 is a flow chart according to one exemplary embodiment.

FIG. 15 is a flow chart according to one exemplary embodiment.

FIG. 16 is a flow chart according to one exemplary embodiment.

FIG. 17 is a flow chart according to one exemplary embodiment.

FIG. 18 is a flow chart according to one exemplary embodiment.

FIG. 19 is a flow chart according to one exemplary embodiment.

FIG. 20 is a flow chart according to one exemplary embodiment.

FIG. 21 is a flow chart according to one exemplary embodiment.

FIG. 22 is a flow chart according to one exemplary embodiment.

FIG. 23 is a flow chart according to one exemplary embodiment.

FIG. 24 is a flow chart according to one exemplary embodiment.

FIG. 25 is a flow chart according to one exemplary embodiment.

FIG. 26 is a flow chart according to one exemplary embodiment.

FIG. 27 is a flow chart according to one exemplary embodiment.

DETAILED DESCRIPTION

The exemplary wireless communication systems and devices described belowemploy a wireless communication system, supporting a broadcast service.Wireless communication systems are widely deployed to provide varioustypes of communication such as voice, data, and so on. These systems maybe based on code division multiple access (CDMA), time division multipleaccess (TDMA), orthogonal frequency division multiple access (OFDMA),3GPP LTE (Long Term Evolution) wireless access, 3GPP LTE-A orLTE-Advanced (Long Term Evolution Advanced), 3GPP2 UMB (Ultra MobileBroadband), WiMax, 3GPP NR (New Radio), or some other modulationtechniques.

In particular, the exemplary wireless communication systems devicesdescribed below may be designed to support one or more standards such asthe standard offered by a consortium named “3rd Generation PartnershipProject” referred to herein as 3GPP, including: R2-162709, “Beam supportin NR”, Intel; R2-162762, “Active Mode Mobility in NR: SINR drops inhigher frequencies”, Ericsson; R3-160947, TR 38.801 V0.1.0, “Study onNew Radio Access Technology; Radio Access Architecture and Interfaces”;R2-164306, “Summary of email discussion [93bis#23][NR] Deploymentscenarios”, NTT DOCOMO; 3GPP RAN2#94 meeting minute; TS 36.213 V15.2.0(2018-06), “E-UTRA; Physical layer procedures (Release 15)”; TS 36.214V15.2.0 (2018-03), “E-UTRA; Physical layer; Measurements (Release 15)”;TS 36.212 V15.2.1 (2018-07), “E-UTRA; Physical layer; Multiplexing andchannel coding (Release 15)”; and Draft Report of 3GPP TSG RAN WG1 #94v0.1.0 (Gothenburg, Sweden, 20-24 Aug. 2018). The standards anddocuments listed above are hereby expressly incorporated by reference intheir entirety.

FIG. 1 shows a multiple access wireless communication system accordingto one embodiment of the invention. An access network 100 (AN) includesmultiple antenna groups, one including 104 and 106, another including108 and 110, and an additional including 112 and 114. In FIG. 1, onlytwo antennas are shown for each antenna group, however, more or fewerantennas may be utilized for each antenna group. Access terminal 116(AT) is in communication with antennas 112 and 114, where antennas 112and 114 transmit information to access terminal 116 over forward link120 and receive information from access terminal 116 over reverse link118. Access terminal (AT) 122 is in communication with antennas 106 and108, where antennas 106 and 108 transmit information to access terminal(AT) 122 over forward link 126 and receive information from accessterminal (AT) 122 over reverse link 124. In a FDD system, communicationlinks 118, 120, 124 and 126 may use different frequency forcommunication. For example, forward link 120 may use a differentfrequency then that used by reverse link 118.

Each group of antennas and/or the area in which they are designed tocommunicate is often referred to as a sector of the access network. Inthe embodiment, antenna groups each are designed to communicate toaccess terminals in a sector of the areas covered by access network 100.

In communication over forward links 120 and 126, the transmittingantennas of access network 100 may utilize beamforming in order toimprove the signal-to-noise ratio of forward links for the differentaccess terminals 116 and 122. Also, an access network using beamformingto transmit to access terminals scattered randomly through its coveragecauses less interference to access terminals in neighboring cells thanan access network transmitting through a single antenna to all itsaccess terminals.

An access network (AN) may be a fixed station or base station used forcommunicating with the terminals and may also be referred to as anaccess point, a Node B, a base station, an enhanced base station, anevolved Node B (eNB), or some other terminology. An access terminal (AT)may also be called user equipment (UE), a wireless communication device,terminal, access terminal or some other terminology.

FIG. 2 is a simplified block diagram of an embodiment of a transmittersystem 210 (also known as the access network) and a receiver system 250(also known as access terminal (AT) or user equipment (UE)) in a MIMOsystem 200. At the transmitter system 210, traffic data for a number ofdata streams is provided from a data source 212 to a transmit (TX) dataprocessor 214.

In one embodiment, each data stream is transmitted over a respectivetransmit antenna. TX data processor 214 formats, codes, and interleavesthe traffic data for each data stream based on a particular codingscheme selected for that data stream to provide coded data.

The coded data for each data stream may be multiplexed with pilot datausing OFDM techniques. The pilot data is typically a known data patternthat is processed in a known manner and may be used at the receiversystem to estimate the channel response. The multiplexed pilot and codeddata for each data stream is then modulated (i.e., symbol mapped) basedon a particular modulation scheme (e.g., BPSK, QPSK, M-PSK, or M-QAM)selected for that data stream to provide modulation symbols. The datarate, coding, and modulation for each data stream may be determined byinstructions performed by processor 230.

The modulation symbols for all data streams are then provided to a TXMIMO processor 220, which may further process the modulation symbols(e.g., for OFDM). TX MIMO processor 220 then provides N_(T) modulationsymbol streams to N_(T) transmitters (TMTR) 222 a through 222 t. Incertain embodiments, TX MIMO processor 220 applies beamforming weightsto the symbols of the data streams and to the antenna from which thesymbol is being transmitted.

Each transmitter 222 receives and processes a respective symbol streamto provide one or more analog signals, and further conditions (e.g.,amplifies, filters, and upconverts) the analog signals to provide amodulated signal suitable for transmission over the MIMO channel. N_(T)modulated signals from transmitters 222 a through 222t are thentransmitted from N_(T) antennas 224 a through 224 t, respectively.

At receiver system 250, the transmitted modulated signals are receivedby N_(R) antennas 252 a through 252 r and the received signal from eachantenna 252 is provided to a respective receiver (RCVR) 254 a through254 r. Each receiver 254 conditions (e.g., filters, amplifies, anddownconverts) a respective received signal, digitizes the conditionedsignal to provide samples, and further processes the samples to providea corresponding “received” symbol stream.

An RX data processor 260 then receives and processes the N_(R) receivedsymbol streams from N_(R) receivers 254 based on a particular receiverprocessing technique to provide N_(T) “detected” symbol streams. The RXdata processor 260 then demodulates, deinterleaves, and decodes eachdetected symbol stream to recover the traffic data for the data stream.The processing by RX data processor 260 is complementary to thatperformed by TX MIMO processor 220 and TX data processor 214 attransmitter system 210.

A processor 270 periodically determines which pre-coding matrix to use(discussed below). Processor 270 formulates a reverse link messagecomprising a matrix index portion and a rank value portion.

The reverse link message may comprise various types of informationregarding the communication link and/or the received data stream. Thereverse link message is then processed by a TX data processor 238, whichalso receives traffic data for a number of data streams from a datasource 236, modulated by a modulator 280, conditioned by transmitters254 a through 254 r, and transmitted back to transmitter system 210.

At transmitter system 210, the modulated signals from receiver system250 are received by antennas 224, conditioned by receivers 222,demodulated by a demodulator 240, and processed by a RX data processor242 to extract the reserve link message transmitted by the receiversystem 250. Processor 230 then determines which pre-coding matrix to usefor determining the beamforming weights then processes the extractedmessage.

Turning to FIG. 3, this figure shows an alternative simplifiedfunctional block diagram of a communication device according to oneembodiment of the invention. As shown in FIG. 3, the communicationdevice 300 in a wireless communication system can be utilized forrealizing the UEs (or ATs) 116 and 122 in FIG. 1 or the base station (orAN) 100 in FIG. 1, and the wireless communications system is preferablythe NR system. The communication device 300 may include an input device302, an output device 304, a control circuit 306, a central processingunit (CPU) 308, a memory 310, a program code 312, and a transceiver 314.The control circuit 306 executes the program code 312 in the memory 310through the CPU 308, thereby controlling an operation of thecommunications device 300. The communications device 300 can receivesignals input by a user through the input device 302, such as a keyboardor keypad, and can output images and sounds through the output device304, such as a monitor or speakers. The transceiver 314 is used toreceive and transmit wireless signals, delivering received signals tothe control circuit 306, and outputting signals generated by the controlcircuit 306 wirelessly. The communication device 300 in a wirelesscommunication system can also be utilized for realizing the AN 100 inFIG. 1.

FIG. 4 is a simplified block diagram of the program code 312 shown inFIG. 3 in accordance with one embodiment of the invention. In thisembodiment, the program code 312 includes an application layer 400, aLayer 3 portion 402, and a Layer 2 portion 404, and is coupled to aLayer 1 portion 406. The Layer 3 portion 402 generally performs radioresource control. The Layer 2 portion 404 generally performs linkcontrol. The Layer 1 portion 406 generally performs physicalconnections.

3GPP standardization activities on next generation (i.e. 5G) accesstechnology have been launched since March 2015. In general, the nextgeneration access technology aims to support the following threefamilies of usage scenarios for satisfying both the urgent market needsand the more long-term requirements set forth by the ITU-R IMT-2020:

eMBB (enhanced Mobile Broadband)

mMTC (massive Machine Type Communications)

URLLC (Ultra-Reliable and Low Latency Communications).

An objective of the 5G study item on new radio access technology is toidentify and develop technology components needed for new radio systemswhich should be able to use any spectrum band ranging at least up to 100GHz. Supporting carrier frequencies up to 100GHz brings a number ofchallenges in the area of radio propagation. As the carrier frequencyincreases, the path loss also increases.

Based on 3GPP R2-162709 and as shown in FIG. 5, an eNB may have multipleTRPs (either centralized or distributed). Each TRP(Transmission/Reception Point) can form multiple beams. The number ofbeams and the number of simultaneous beams in the time/frequency domaindepend on the number of antenna array elements and the RF (RadioFrequency) at the TRP.

Potential mobility type for NR can be listed as follows:

Intra-TRP mobility

Inter-TRP mobility

Inter-NR eNB mobility

Based on 3GPP R3-160947, the scenarios illustrated in FIGS. 6 and 7should be considered for support by the NR radio network architecture.

Based on 3GPP R2-164306, the following scenarios in terms of cell layoutfor standalone NR are captured to be studied:

Macro cell only deployment

Heterogeneous deployment

Small cell only deployment

Based on 3GPP RAN2#94 meeting minutes, 1 NR eNB corresponds to 1 or manyTRPs. Two levels of network controlled mobility:

RRC driven at “cell” level.

Zero/Minimum RRC involvement (e.g. at MAC/PHY)

FIGS. 8 to 11 show some examples of the concept of a cell in 5G NR. FIG.8 is a reproduction of a portion of FIG. 1 of 3GPP R2-163879, and showsexemplary different deployment scenarios with single TRP cell. FIG. 9 isa reproduction of a portion of FIG. 1 of 3GPP R2-163879, and showsexemplary different deployment scenarios with multiple TRP cells. FIG.10 is a reproduction of FIG. 3 of 3GPP R2-162210, and shows an exemplary5G cell comprising a 5G node with multiple TRPs. FIG. 11 is areproduction of FIG. 1 of 3GPP R2-163471, and shows an exemplarycomparison between a LTE cell and a NR cell.

3GPP TS 36.213 specifies the UE procedure for determining the subset ofresources to be reported to higher layers in PSSCH (Physical SidelinkShared Channel) resource selection in sidelink transmission mode 4 asfollows:

-   14.1.1.6 UE procedure for determining the subset of resources to be    reported to higher layers in PSSCH resource selection in sidelink    transmission mode 4    When requested by higher layers in subframe n, the UE shall    determine the set of resources to be reported to higher layers for    PSSCH transmission according to the following steps. Parameters    L_(subCH) the number of sub-channels to be used for the PSSCH    transmission in a subframe, P_(rsvp_TX) the resource reservation    interval, and prio_(TX) the priority to be transmitted in the    associated SCI format 1 by the UE are all provided by higher layers.    C_(resel) is determined according to Subclause 14.1.1.4B.    If partial sensing is not configured by higher layers then the    following steps are used:    -   1) A candidate single-subframe resource for PSSCH transmission        R_(x,y) is defined as a set of L_(subCH) contiguous sub-channels        with sub-channel x+j in subframe t_(y) ^(SL) where j=0, . . . ,        L_(subCH)−1. The UE shall assume that any set of L_(subCH)        contiguous sub-channels included in the corresponding PSSCH        resource pool (described in 14.1.5) within the time interval        [n+T₁, n+T₂] corresponds to one candidate single-subframe        resource, where selections of T₁ and T₂ are up to UE        implementations under T₁≤4 and 20≤T₂≤100. UE selection of T₂        shall fulfil the latency requirement. The total number of the        candidate single-subframe resources is denoted by M_(total).    -   2) The UE shall monitor subframes t_(n′−10×P) _(step) ₊₁ ^(SL),        t_(n′−10×P) _(step) ₊₁ ^(SL), t_(n′−1) ^(SL) except for those in        which its transmissions occur, where t_(n′) ^(SL)=n if subframe        n belongs to the set (t₀ ^(SL), t₁ ^(SL), . . . , t_(T) _(max)        ^(SL)), otherwise subframe t_(n′) ^(SL) is the first subframe        after subframe n belonging to the set (t₀ ^(SL), t₁ ^(SL), . . .        , t_(T) _(max) ^(SL)). The UE shall perform the behaviour in the        following steps based on PSCCH decoded and S-RSSI measured in        these subframes.    -   3) The parameter Th_(ab) is set to the value indicated by the        i-th SL-ThresPSSCH-RSRP field in SL-ThresPSSCH-RSRP-List where        i=a*8+b+1.    -   4) The set S_(A) is initialized to the union of all the        candidate single-subframe resources. The set S_(B) is        initialized to an empty set.    -   5) The UE shall exclude any candidate single-subframe resource        R_(x,y) from the set S_(A) if it meets all the following        conditions:        -   the UE has not monitored subframe t_(z) ^(SL) in Step 2.        -   there is an integer j which meets            y+j×P_(rsvp_TX)=z+P_(step)×k×q where j=0, 1, . . . ,            C_(resel)−1, P′_(rsvp_TX)=P_(step)×P_(rsvp_TX)/100, k is any            value allowed by the higher layer parameter            restrictResourceReservationPeriod and q=1,2, . . . , Q.            Here,

$Q = \frac{1}{k}$

if k<1 and n−z≤P_(step)×k, where t_(n′) ^(SL)=n if subframe n belongs tothe set t₀ ^(SL), t₁ ^(SL), . . . , t_(T) _(max) ^(SL), otherwisesubframe t_(n′) ^(SL) is the first subframe belonging to the set t₀^(SL), t₁ ^(SL), . . . , t_(T) _(max) ^(SL) after subframe n; and Q=1otherwise.

-   -   6) The UE shall exclude any candidate single-subframe resource        R_(x,y) from the set S_(A) if it meets all the following        conditions:        -   the UE receives an SCI format 1 in subframe t_(m) ^(SL), and            “Resource reservation” field and “Priority” field in the            received SCI format 1 indicate the values P_(rsvp_RX) and            prio_(RX), respectively according to Subclause 14.2.1.        -   PSSCH-RSRP measurement according to the received SCI format            1 is higher than Th_(prio) _(TX) _(,prio) _(RX) .        -   the SCI format received in subframe t_(m) ^(SL) or the same            SCI format 1 which is assumed to be received in subframe(s)            t_(m+q×P) _(step) _(×P) _(rsvp_RX) ^(SL) determines            according to 14.1.1.4C the set of resource blocks and            subframes which overlaps with R_(x,y+j×P′) _(rsvp_TX) for            q=1, 2, . . . , Q and j=0, 1, . . . , C_(reset)−1. Here,

$Q = \frac{1}{P_{rsvp\_ RX}}$

if P_(rsvp_RX)<1 and n′−m≤P_(step)×P_(rsvp_RX), where t_(n′) ^(SL)=n ifsubframe n belongs to the set (t₀ ^(SL), t₁ ^(SL), . . . , t_(T) _(max)^(SL)), otherwise subframe t_(n′) ^(SL) is the first subframe aftersubframe n belonging to the set (t₀ ^(SL), t₁ ^(SL), . . . , t_(T)_(max) ^(SL)); otherwise Q=1.

-   -   7) If the number of candidate single-subframe resources        remaining in the set S_(A) is smaller than 0.2·M_(total), then        Step 4 is repeated with Th_(a,b) increased by 3 dB.    -   8) For a candidate single-subframe resource R_(x,y) remaining in        the set S_(A), the metric E_(x,y) is defined as the linear        average of S-RSSI measured in sub-channels x+k for k=0, . . . ,        L_(subCH)−1 in the monitored subframes in Step 2 that can be        expressed by t_(y−P) _(step) _(*j) ^(SL) for a non-negative        integer j if P_(rsvp_TX)≥100, and t_(y−P′) _(rsvp_TX) ^(SL) for        a non-negative integer j otherwise.    -   9) The UE moves the candidate single-subframe resource R_(x,y)        with the smallest metric E_(x,y) from the set S_(A) to S_(B).        This step is repeated until the number of candidate        single-subframe resources in the set S_(B) becomes greater than        or equal to 0.2·M_(total) ,        The UE shall report set S_(B) to higher layers.

3GPP TS 36.214 specifies some measurements for sidelink transmission asfollows:

-   5.1.28 Sidelink Received Signal Strength Indicator (S-RSSI)

Definition Sidelink RSSI (S-RSSI) is defined as the linear average ofthe total received power (in [W]) per SC-FDMA symbol observed by the UEonly in the configured sub-channel in SC-FDMA symbols 1, 2, . . . , 6 ofthe first slot and SC-FDMA symbols 0, 1, . . . , 5 of the second slot ofa subframe The reference point for the S-RSSI shall be the antennaconnector of the UE. If receiver diversity is in use by the UE, thereported value shall not be lower than the corresponding S-RSSI of anyof the individual diversity branches Applicable for RRC_IDLEintra-frequency, RRC_IDLE inter-frequency, RRC_CONNECTEDintra-frequency, RRC_CONNECTED inter-frequency

-   5.1.29 PSSCH Reference Signal Received Power (PSSCH-RSRP)

Definition PSSCH Reference Signal Received Power (PSSCH-RSRP) is definedas the linear average over the power contributions (in [W]) of theresource elements that carry demodulation reference signals associatedwith PSSCH, within the PRBs indicated by the associated PSCCH. Thereference point for the PSSCH-RSRP shall be the antenna connector of theUE. If receiver diversity is in use by the UE, the reported value shallnot be lower than the corresponding PSSCH-RSRP of any of the individualdiversity branches Applicable for RRC_IDLE intra-frequency, RRC_IDLEinter-frequency, RRC_CONNECTED intra-frequency, RRC_CONNECTEDinter-frequency NOTE: The power per resource element is determined fromthe energy received during the useful part of the symbol, excluding theCP.

3GPP TS 36.212 specifies the UE procedure for sidelink transmission mode3, which is V2X (Vehicle-to-Everything) transmission scheduled fromnetwork node, as follows:

-   14.1 Physical Sidelink Shared Channel related procedures-   14.1.1 UE procedure for transmitting the PSSCH-   If the UE transmits SCI format 1 on PSCCH according to a PSCCH    resource configuration in subframe n, then for the corresponding    PSSCH transmissions of one TB    -   for sidelink transmission mode 3,        -   the set of subframes and the set of resource blocks are            determined using the subframe pool indicated by the PSSCH            resource configuration (described in Subclause 14.1.5) and            using “Retransmission index and Time gap between initial            transmission and retransmission” field and “Frequency            resource location of the initial transmission and            retransmission” field in the SCI format 1 as described in            Subclause 14.1.1.4A.-   14.1.1.4A UE procedure for determining subframes and resource blocks    for transmitting PSSCH for sidelink transmission mode 3-   If the UE has a configured sidelink grant (described in [8]) in    subframe t_(n) ^(SL) with the corresponding PSCCH resource m    (described in Subclause 14.2.4), the resource blocks and subframes    of the corresponding PSSCH transmissions are determined according to    14.1.1.4C.-   If the UE has a configured sidelink grant (described in [8]) for an    SL SPS configuration activated by Subclause 14.2.1 and if a set of    sub-channels in subframe t_(m) ^(SL) is determined as the time and    frequency resource for PSSCH transmission corresponding to the    configured sidelink grant (described in [8]) of the SL SPS    configuration, the same set of sub-channels in subframes t_(m+j×P′)    _(SPS) ^(SL) are also determined for PSSCH transmissions    corresponding to the same sidelink grant where j=1,2, . . . ,    P′_(SPS)=P_(step)×P_(SPS)/100, and (t₀ ^(SL), t₁ ^(SL), t₂ ^(SL), .    . . ) is determined by Subclause 14.1.5. Here, P_(SPS) is the    sidelink SPS interval of the corresponding SL SPS configuration.-   14.1.5 UE procedure for determining resource block pool and subframe    pool for sidelink transmission mode 3 and 4-   The set of subframes that may belong to a PSSCH resource pool for    sidelink transmission mode 3 or 4 is denoted by (t₀ ^(SL), t₁ ^(SL),    . . . , t_(T) _(max) ^(SL)) where . . .-   The UE determines the set of subframes assigned to a PSSCH resource    pool as follows:    -   A bitmap (b₀, b₁, . . . , b_(L) _(bitmap) ) associated with the        resource pool is used where L_(bitmap) the length of the bitmap        is configured by higher layers.    -   A subframe t_(k)        ^(SL)(0≤k≤(10240−N_(slss)−N_(dssf)−N_(reserved))) belongs to the        subframe pool if b_(k′)=1 where k′=k mod L_(bitmap).-   The UE determines the set of resource blocks assigned to a PSSCH    resource pool as follows:    -   The resource block pool consists of N_(subCH) sub-channels where        N_(subCH) is given by higher layer parameter numSubchannel.    -   The sub-channel m for m=0,1, . . . , N_(subCH)−1 consists of a        set of n_(subCHsize) contiguous resource blocks with the        physical resource block number        n_(PRB)=n_(subCHRBstart)m*n_(subCHsize)+j for j=0,1, . . . ,        n_(subCHsize)−1 where n_(subCHRBstart) and n_(subCHsize) are        given by higher layer parameters startRBSubchannel and        sizeSubchannel, respectively-   14.2 Physical Sidelink Control Channel related procedures-   For sidelink transmission mode 3, if a UE is configured by higher    layers to receive DCI format 5A with the CRC scrambled by the    SL-V-RNTI or SL-SPS-V-RNTI, the UE shall decode the PDCCH/EPDCCH    according to the combination defined in Table 14.2-2. A UE is not    expected to receive DCI format 5A with size larger than DCI format 0    in the same search space that DCI format 0 is defined on.-   [Table 14.2-2 of 3GPP TS 36.212 V15.2.1, entitled “PDCCH/EPDCCH    configured by SL-V-RNTI or SL-SPS-V-RNTI”, is reproduced as FIG. 13]-   The carrier indicator field value in DCI format 5A corresponds to    v2x-InterFreqInfo.-   14.2.1 UE procedure for transmitting the PSCCH-   For sidelink transmission mode 3,    -   The UE shall determine the subframes and resource blocks for        transmitting SCI format 1 as follows:        -   SCI format 1 is transmitted in two physical resource blocks            per slot in each subframe where the corresponding PSSCH is            transmitted.        -   If the UE receives in subframe n DCI format 5A with the CRC            scrambled by the SL-V-RNTI, one transmission of PSCCH is in            the PSCCH resource L_(Init) (described in Subclause 14.2.4)            in the first subframe that is included in (t₀ ^(SL), t₁            ^(SL), t₂ ^(SL), . . . ) and that starts not earlier than

$T_{DL} - {\frac{N_{T\; A}}{2} \times T_{S}} + {( {4 + m} ) \times {10^{- 3}.}}$

L_(Init) is the value indicated by “Lowest index of the sub-channelallocation to the initial transmission” associated with the configuredsidelink grant (described in [8]), (t₀ ^(SL), t₁ ^(SL), t₂ ^(SL), . . .) is determined by Subclause 14.1.5, the value m is indicated by ‘SLindex’ field in the corresponding DCI format 5A according to Table14.2.1-1 if this field is present and m=0 otherwise, T_(DL) is the startof the downlink subframe carrying the DCI, and N_(TA) and T_(S) aredescribed in [3].

-   -   -   If “Time gap between initial transmission and            retransmission” in the configured sidelink grant (described            in [8]) is not equal to zero, another transmission of PSCCH            is in the PSCCH resource L_(ReTX) in subframe t_(q+SF)            _(gap) ^(SL), where SF_(gap) is the value indicated by “Time            gap between initial transmission and retransmission” field            in the configured sidelink grant, subframe t_(q) ^(SL)            corresponds to the subframe n+k_(init)·L_(ReTX) corresponds            to the value n_(subCH) ^(start) determined by the procedure            in Subclause 14.1.1.4C with the RIV set to the value            indicated by “Frequency resource location of the initial            transmission and retransmission” field in the configured            sidelink grant.

    -   If the UE receives in subframe n DCI format 5A with the CRC        scrambled by the SL-SPS-V-RNTI, the UE shall consider the        received DCI information as a valid sidelink semi-persistent        activation or release only for the SPS configuration indicated        by the SL SPS configuration index field. If the received DCI        activates an SL SPS configuration, one transmission of PSCCH is        in the PSCCH resource L_(Init) (described in Subclause 14.2.4)        in the first subframe that is included in (t₀ ^(SL), t₁ ^(SL),        t₂ ^(SL), . . . ) and that starts not earlier than

$T_{DL} - {\frac{N_{TA}}{2} \times {T_{S}( {4 + m} )} \times {10^{- 3}.}}$

L_(Init) is the value indicated by “Lowest index of the sub-channelallocation to the initial transmission” associated with the configuredsidelink grant (described in [8]), (t₀ ^(SL), t₁ ^(SL), t₂ ^(SL), . . .) is determined by Subclause 14.1.5, the value m is indicated by ‘SLindex’ field in the corresponding DCI format 5A according to Table14.2.1-1 if this field is present and m=0 otherwise, T_(DL) is the startof the downlink subframe carrying the DCI, and N_(TA) and T_(S) aredescribed in [3].

-   -   -   If “Time gap between initial transmission and            retransmission” in the configured sidelink grant (described            in [8]) is not equal to zero, another transmission of PSCCH            is in the PSCCH resource L_(ReTX) in subframe t_(q|SF)            _(gap) ^(SL), where SF_(gap) is the value indicated by “Time            gap between initial transmission and retransmission” field            in the configured sidelink grant, subframe t_(q) ^(SL)            corresponds to the subframe n+k_(init)·L_(ReTX) corresponds            to the value n_(subCH) ^(start) determined by the procedure            in Subclause 14.1.1.4C with the RIV set to the value            indicated by “Frequency resource location of the initial            transmission and retransmission” field in the configured            sidelink grant.

3GPP TS 36.212 specifies DCI (Downlink Control Information) format 5Afrom network node for scheduling PSCCH (Physical Shared Control Channel)transmission on PC5 interface, and SCI (Sidelink Control Information)format 1 from UE for scheduling PSSCH transmission on PC5 interface asfollows:

-   5.3.3.1.9A Format 5A-   DCI format 5A is used for the scheduling of PSCCH, and also contains    several SCI format 1 fields used for the scheduling of PSSCH.-   The following information is transmitted by means of the DCI format    5A:    -   Carrier indicator—3 bits. This field is present according to the        definitions in [3].    -   Lowest index of the subchannel allocation to the initial        transmission-[log₂(N_(subchannel) ^(SL))] bits as defined in        section 14.1.1.4C of [3].    -   SCI format 1 fields according to 5.4.3.1.2:        -   Frequency resource location of initial transmission and            retransmission.        -   Time gap between initial transmission and retransmission.    -   SL index—2 bits as defined in section 14.2.1 of [3] (this field        is present only for cases with TDD operation with        uplink-downlink configuration 0-6).-   When the format 5A CRC is scrambled with SL-SPS-V-RNTI, the    following fields are present:    -   SL SPS configuration index—3 bits as defined in section 14.2.1        of [3].    -   Activation/release indication—1 bit as defined in section 14.2.1        of [3].-   If the number of information bits in format 5A mapped onto a given    search space is less than the payload size of format 0 mapped onto    the same search space, zeros shall be appended to format 5A until    the payload size equals that of format 0 including any padding bits    appended to format 0.-   If the format 5A CRC is scrambled by SL-V-RNTI and if the number of    information bits in format 5A mapped onto a given search space is    less than the payload size of format 5A with CRC scrambled by    SL-SPS-V-RNTI mapped onto the same search space and format 0 is not    defined on the same search space, zeros shall be appended to format    5A until the payload size equals that of format 5A with CRC    scrambled by SL-SPS-V-RNTI.-   5.4.3.1.2 SCI format 1-   SCI format 1 is used for the scheduling of PSSCH.-   The following information is transmitted by means of the SCI format    1:    -   Priority—3 bits as defined in section 4.4.5.1 of [7].    -   Resource reservation—4 bits as defined in section 14.2.1 of [3].    -   Frequency resource location of initial transmission and        retransmission—[log₂(N_(subchannel) ^(SL)(N_(subchannel)        ^(SL)+1)2)] bits as defined in section 14.1.1.4C of [3].    -   Time gap between initial transmission and retransmission—4 bits        as defined in section 14.1.1.4C of [3].    -   Modulation and coding scheme—5 bits as defined in section 14.2.1        of [3].    -   Retransmission index—1 bit as defined in section 14.2.1 of [3].    -   Reserved information bits are added until the size of SCI format        1 is equal to 32 bits. The reserved bits are set to zero.

In RAN1 #94 meeting (as discussed in the Draft Report of 3GPP TSG RANWG1 #94 v0.1.0 (Gothenburg, Sweden, 20-24 Aug. 2018), RANI has thefollowing agreements about NR V2X.

Agreements:

-   -   RAN1 to study the following topics for the SL enhancement for        unicast and/or groupcast. Other topics are not precluded.        -   HARQ feedback        -   CSI acquisition        -   Open loop and/or closed-loop power control        -   Link adaptation        -   Multi-antenna transmission scheme

Agreements:

-   -   At least PSCCH and PSSCH are defined for NR V2X. PSCCH at least        carries information necessary to decode PSSCH.        -   Note: PSBCH will be discussed in the synchronization agenda.    -   RAN1 continues study on the necessity of other channels.    -   Further study on        -   Whether/which sidelink feedback information is carried by            PSCCH or by another channel/signal.        -   Whether/which information to assist resource allocation            and/or schedule UE's transmission resource(s) is carried by            PSCCH or by another channel/signal.        -   PSCCH format(s) and content(s) for unicast, groupcast, and            broadcast

Agreements:

RANI to continue study on multiplexing physical channels considering atleast the above aspects:

-   -   Multiplexing of PSCCH and the associated PSSCH (here, the        “associated” means that the PSCCH at least carries information        necessary to decode the PSSCH).        -   Study further the following options:            -   Option 1: PSCCH and the associated PSSCH are transmitted                using non-overlapping time resources.                -   Option 1A: The frequency resources used by the two                    channels are the same.                -   Option 1B: The frequency resources used by the two                    channels can be different.            -   Option 2: PSCCH and the associated PSSCH are transmitted                using non-overlapping frequency resources in the all the                time resources used for transmission. The time resources                used by the two channels are the same.            -   Option 3: A part of PSCCH and the associated PSSCH are                transmitted using overlapping time resources in                non-overlapping frequency resources, but another part of                the associated PSSCH and/or another part of the PSCCH                are transmitted using non-overlapping time resources.

Agreements:

-   At least two sidelink resource allocation modes are defined for    NR-V2X sidelink communication    -   Mode 1: Base station schedules sidelink resource(s) to be used        by UE for sidelink transmission(s)    -   Mode 2: UE determines (i.e. base station does not schedule)        sidelink transmission resource(s) within sidelink resources        configured by base station/network or pre-configured sidelink        resources

Notes:

-   -   eNB control of NR sidelink and gNB control of LTE sidelink        resources will be separately considered in corresponding agenda        items.    -   Mode-2 definition covers potential sidelink radio-layer        functionality or resource allocation sub-modes (subject to        further refinement including merging of some or all of them)        where        -   a) UE autonomously selects sidelink resource for            transmission        -   b) UE assists sidelink resource selection for other UE(s)        -   c) UE is configured with NR configured grant (type-1 like)            for sidelink transmission        -   d) UE schedules sidelink transmissions of other UEs    -   RAN1 to continue study details of resource allocation modes for        NR-V2X sidelink communication

One or multiple of following terminologies may be used hereafter:

-   -   BS: A network central unit or a network node in NR which is used        to control one or multiple TRPs which are associated with one or        multiple cells. Communication between BS and TRP(s) is via        fronthaul. BS could also be referred to as central unit (CU),        eNB, gNB, or NodeB.    -   TRP: A transmission and reception point provides network        coverage and directly communicates with UEs. TRP could also be        referred to as distributed unit (DU) or network node.    -   Cell: A cell is composed of one or multiple associated TRPs,        i.e. coverage of the cell is composed of coverage of all        associated TRP(s). One cell is controlled by one BS. Cell could        also be referred to as TRP group (TRPG).    -   NR-PDCCH: A channel carries downlink control signal which is        used to control communication between a UE and a network side. A        network transmits NR-PDCCH on configured control resource set        (CORESET) to the UE.    -   UL-control signal: An UL-control signal may be scheduling        request(SR), channel state information(CSI), HARQ-ACK/NACK for        downlink transmission    -   Slot: a scheduling unit in NR. Slot duration is 14 OFDM symbols.    -   Mini-slot: A scheduling unit with duration less than 14 OFDM        symbols.    -   Slot format information (SFI): Information of slot format of        symbols in a slot. A symbol in a slot may belong to following        type: downlink, uplink, unknown or other. The slot format of a        slot could at least convey transmission direction of symbols in        the slot.    -   DL common signal: Data channel carrying common information that        targets for multiple UEs in a cell or all UEs in a cell.        Examples of DL common signal could be system information,        paging, RAR.

One or multiple of following assumptions for network side may be usedhereafter:

-   -   Downlink timing of TRPs in the same cell are synchronized.    -   RRC layer of network side is in BS.

One or multiple of following assumptions for UE side may be usedhereafter:

-   -   There are at least two UE (RRC) states: connected state (or        called active state) and non-connected state (or called inactive        state or idle state). Inactive state may be an additional state        or belong to connected state or non-connected state.

For LTE V2X and/or P2X transmission, there are generally at least twotransmission modes: one is scheduled via network, such as sidelinktransmission mode 3 (as discussed in 3GPP TS 36.214); and another one issensing-based transmission, such as sidelink transmission mode 4 (asdiscussed in 3GPP TS 36.214). Since the sensing-based transmission isnot scheduled via network, the UE requires performing sensing beforeselecting a resource for transmission, in order to avoid resourcecollision and interference from or in other UEs.

For the sensing-based resource selection procedure, as shown in FIG. 12,the UE have a candidate resource set comprising multiple candidateresources. The available candidate resource set is restricted with timeinterval [n+T₁,n+T₂]. The restricted time interval may be differentdepending on whether partially sensing is configure or not. Full sensingmay mean that partially sensing is not configured. In one embodiment, acandidate resource may mean one candidate single-subframe resource. Onecandidate resource may comprise one or multiple resource units. Theresource unit may be a subchannel. In one embodiment, the resource unitmay comprise multiple (physical) resource blocks in a TTI (TransmissionTime Interval). The TTI may be a subframe in LTE.

Based on sensing within a sensing duration, the UE may generate a validresource set, wherein the valid resource set is a subset of thecandidate resource set. The generation of the valid resource set may beperformed via excluding some candidate resources from the candidateresource set, as shown for instance in step 2-1 and step 2-2 of FIG. 12.The generation of the valid resource set may be performed via selectingsome valid candidate resources, as shown for instance in step 3-1 ofFIG. 12. And then, the UE may select one or some valid resources fromthe valid resource set to perform transmission from the UE. The validresource selection for transmission may be randomly selected from thevalid resource set, as shown for instance in step 3-2 of FIG. 12.

As discussed in 3GPP TS 36.214, the first excluding step is if the UEdoes not monitor/sense a TTI z, the UE cannot expect whether thecandidate resources in TTI “z+P_(any)” are occupied or not, whereinP_(any) means any possible periodicity for transmission. For instance,the first excluding step is shown as step 2-1 of FIG. 12. For the caseof P_(any)>=100 ms, the UE excludes the candidate resources in TTI“z+P_(any)” and excludes the candidates resources for which the UE mayhave possible transmission occurred in TTI “ z+P_(any)”. For the case ofP_(any)<100 ms, the UE excludes the candidate resources in TTI“z+q·P_(any)” and excludes the candidates resources for which the UE mayhave a possible transmission occurred in TTI “z+q·P_(any)”, wherein q is1, 2, . . . , 100/P_(any) . The parameter q means that the UE excludesmultiple candidate resources with period P_(any) within time interval[z, z+100]. The possible transmission may mean a transmission on aselected valid resource. The possible transmission may also mean aperiodic transmission of a transmission on a selected valid resource.Moreover, P_(any) means any possible periodicity configured by higherlayer.

The second excluding step is if the UE receives/detects a controlsignaling in a TTI m, the UE may exclude the candidate resourcesaccording to the received control signaling. For instance, the secondexcluding step is shown as step 2-2 of FIG. 12. More specifically, ifthe UE receives or detects a control signaling scheduling a transmissionin a TTI m and the measurement result of the scheduled transmissionand/or the control signal is over a threshold, the UE may exclude thecandidate resources according to the received control signaling. Themeasurement result may be RSRP. More specifically, the measurementresult may be PSSCH-RSRP. The control signaling may indicate theresources of the scheduled transmission and/or periodicity of thescheduled transmission, P_(RX). The excluded candidate resourcesaccording to the received control signaling are the resources of nextone scheduled transmission based on the resources of the scheduledtransmission and periodicity of the scheduled transmission, such as forthe case of P_(RX)>=100 ms. Moreover, the excluded candidate resourcesaccording to the received control signaling are the resources of nextmultiple scheduled transmissions based on the resources of the scheduledtransmission and periodicity of the scheduled transmission, such as forthe case of P_(RX)<100 ms. The next multiple scheduled transmissions maybe with period P_(RX) within time interval [m, m+100]. If the controlsignaling indicates that there is no next scheduled transmission or thecontrol signaling indicates that the resource of scheduled transmissionis not kept in next time or the control signaling indicates that thescheduled transmission is the last transmission from the UE transmittingthe control signaling or the control signaling indicates that theperiodicity of the scheduled transmission is indicated as zero, the UEmay not exclude candidate resources according to the received controlsignaling.

After the first excluding step and the second excluding step, the UE mayselect some valid candidate resources from the remaining candidateresources, such as step 3-1 shown in FIG. 12. The UE may measureresources in the sensing duration, wherein the measured resources areassociated with the remaining candidate resources after step 2-1 andstep 2-2 of FIG. 12. More specifically, for a remaining candidateresource, the associated measured resources in the sensing duration arein the occasions with multiple times of a time period from the remainingcandidate resources. For instance, if the time period is 100 TTIs, theassociated measured resources in the sensing duration are in the TTI“n-j·100”, j is positive integer, for a remaining candidate resource inTTI n.

Moreover, the associated measured resources in the sensing duration arewith the same frequency resources as the remaining candidate resource.More specifically, the measurement is S-RSSI measurement. Based on themeasurement, the UE can derive metric for each remaining candidateresource. The metric for a remaining candidate resource may be linearaverage of S-RSSI measured from its associated measured resources in thesensing duration. And then, the UE may select valid candidate resourcesbased on the metric of each remaining candidate resource.

In one embodiment, an action could be a remaining candidate resourcewith the smallest metric is selected as valid candidate resource andmoved into a valid resource set. The action is repeated until the UEselects a number of remaining candidate resources as valid candidateresources and moves the number of remaining candidate resources into thevalid resource set. For instance, the number is larger than or equal to20% of total candidate resources. The number is larger than or equal to20% of cardinality of the candidate resource set.

Based on the current (partially) sensing procedure, the UE can determinethe valid resource set. The valid resource set may be reported to higherlayers for transmission from the UE. The UE may select one or some validresources from the valid resource set to perform transmission from theUE. The transmission from the UE may be PSSCH transmission. Thetransmission from the UE may be sidelink transmission. In oneembodiment, the transmission from the UE may be device-to-devicetransmission.

In NR V2X, at least two sidelink resource allocation modes are definedfor NR-V2X sidelink communication. Mode 1 is that base station canschedule sidelink resource(s) to be used by UE for sidelinktransmission(s). Mode 2 is that UE determines (i.e. base station doesnot schedule) sidelink transmission resource(s) within sidelinkresources configured by base station/network or pre-configured sidelinkresources. Mode 3 in LTE V2X may be a start point or basis for studymode 1 in NR V2X. Mode 4 in LTE V2X may be a start point or basis forstudy mode 2 in NR V2X.

Moreover, NR V2X has requirement of high reliability and high throughputrequirement. Thus, it is considered to support HARQ (Hybrid AutomaticRepeat Request) feedback for unicast and/or groupcast. It means that atransmitting device transmits a sidelink data transmission to areceiving device, and then the receiving device may transmit HARQfeedback to the transmitting device. If the HARQ feedback is ACK, it maymean the receiving device receives and decodes the sidelink datatransmission successfully.

When the transmitting device receives the HARQ feedback as ACK, thetransmitting device may transmit another new sidelink data transmissionto the receiving device. If the HARQ feedback is NACK, it may mean thereceiving device does not receive and decode the sidelink datatransmission successfully. When the transmitting device receives theHARQ feedback as NACK, the transmitting device may retransmit thesidelink data transmission to the receiving device. Since the sidelinkdata retransmission carries the same data packet as the sidelink datatransmission, the receiving device may combine the sidelink datatransmission and sidelink data retransmission and then perform decodingfor the data packet. The combining can increase possibility of decodingsuccessfully.

However, how to perform the HARQ feedback transmission is not clear.Also, the resource for HARQ feedback transmission needs some design,since both the transmitting device and the receiving device should havethe same understanding about the resource for HARQ feedbacktransmission. The following methods are some methods to derive feedbackresource for sidelink transmission or reception.

I. Method a

The general concept of Method a is that a sidelink feedback resource maybe associated with a sidelink control resource and/or sidelink dataresource. The association may be known by devices comprising atransmitting device and a receiving device. The association may be(pre)configured or specified. In one embodiment, the sidelink feedbackresource may be derived based on the sidelink control resource and/orthe sidelink data resource. There may be no explicit indication, in asidelink control information, for the sidelink feedback resource. Theremay be no field in the sidelink control information for indicating thesidelink feedback resource.

More specifically, given the association, when the transmitting devicetransmits or delivers a sidelink control information in sidelink controltransmission on the sidelink control resource and performs sidelink datatransmission on the sidelink data resource, the transmitting device willmonitor or receive the associated sidelink feedback resource foracquiring feedback information. Furthermore, given the association, whenthe receiving device receives the sidelink control information on thesidelink control resource and receives the sidelink data transmission onthe sidelink data resource, the receiving device may deliver feedbackinformation in feedback transmission on the associated sidelink feedbackresource.

In one embodiment, the sidelink control information may allocate orindicate the sidelink data resource. The receiving device may deliverfeedback information in the feedback transmission on the sidelinkfeedback resource based on whether data delivered in the sidelink datatransmission is decoded successfully or not. The feedback informationmay be positive acknowledgment or ACK, which may mean successfulreception or decoding of data transmission. The feedback information mayalso be non-positive acknowledgment or NACK, which may meannon-successful reception or decoding of data transmission.

In one embodiment, if the transmitting device performs N sidelink datatransmissions, for delivering the same data, on N sidelink dataresources respectively, there may be N associated sidelink feedbackresources. N may be a integer larger than or equal to one. In oneembodiment, the receiving device may deliver feedback information infeedback transmission(s) in the N associated sidelink feedbackresources. The receiving device may deliver feedback information infeedback transmission(s) in part of the N associated sidelink feedbackresources (even though the receiving device may receive the N sidelinkdata transmissions).

In one example, the transmitting device could perform 4 sidelink datatransmissions for delivering the same data. If the receiving devicedecodes the data successfully via two of the 4 sidelink datatransmissions (the receiving device does not decode the datasuccessfully via one of the 4 sidelink data transmissions), thereceiving device may deliver positive acknowledgement (e.g. ACK) infeedback transmissions in the first and second sidelink feedbackresources of the 4 associated sidelink feedback resources.Alternatively, the receiving device may deliver non-positiveacknowledgement (e.g. NACK) in feedback transmissions in the firstsidelink feedback resource of the 4 associated sidelink feedbackresources and deliver positive acknowledgement (e.g. ACK) in feedbacktransmissions in the second sidelink feedback resources of the 4associated sidelink feedback resources.

In one embodiment, the receiving device may not perform feedbacktransmission in the third and fourth sidelink feedback resources of the4 associated sidelink feedback resources. Alternatively, the receivingdevice may deliver positive acknowledgement (e.g. ACK) in feedbacktransmission in the third and fourth sidelink feedback resources of the4 associated sidelink feedback resources. If the receiving devicedecodes the data successfully via one of the 4 sidelink datatransmissions, the receiving device may deliver positive acknowledgement(e.g. ACK) in feedback transmissions in the first sidelink feedbackresource of the 4 associated sidelink feedback resources. In oneembodiment, the receiving device may not perform feedback transmissionin the second, third and fourth sidelink feedback resources of the 4associated sidelink feedback resources. Alternatively, the receivingdevice may deliver positive acknowledgement (e.g. ACK) in feedbacktransmission in the second, third and fourth sidelink feedback resourcesof the 4 associated sidelink feedback resources. If the receiving devicedoes not decode the data successfully via the 4 sidelink datatransmissions, the receiving device may deliver non-positiveacknowledgement (e.g. NACK) in feedback transmissions in the 4associated sidelink feedback resources.

If the sidelink data resource and/or the sidelink control resource arescheduled/allocated by base station, e.g. mode 1 in NR V2X and/or mode 3in LTE V2X, the base station does not need to explicitly indicate theassociated sidelink feedback resource. Since the transmitting device andthe receiving device can derive the sidelink feedback resource based onthe sidelink control resource and/or the sidelink data resource. In oneembodiment, the base station may transmit a downlink control informationto indicate the sidelink data resource and/or the sidelink controlresource. The downlink control information may not indicate the sidelinkfeedback resource.

If the sidelink data resource and/or the sidelink control resource aredetermined by device (i.e. base station does not schedule), e.g. mode 2in NR V2X and/or mode 4 in LTE V2X, the transmitting device may performsensing procedure on a sidelink data resource pool for determining thesidelink data resource based on the sensing result of the sidelink dataresource pool. In one embodiment, the transmitting device may performsensing procedure on a sidelink control resource pool for determiningthe sidelink control resource based on the sensing result of thesidelink control resource pool. The transmitting device may not performsensing procedure on a sidelink feedback resource pool for determiningthe sidelink feedback resource.

Alternatively, the transmitting device may perform sensing procedure ona sidelink feedback resource pool for determining the sidelink feedbackresource or ensuring the associated feedback resource is available orclear. The receiving device may not perform sensing procedure on thesidelink feedback resource pool for determining the sidelink feedbackresource. The transmitting device and the receiving device could derivethe sidelink feedback resource based on the determined sidelink controlresource and/or the determined sidelink data resource. The sidelinkfeedback transmission resource transmitted by the receiving device couldbe reserved or occupied by the transmitting device. The transmittingdevice could reserve or occupy the sidelink feedback transmissionresource in response of determining or occupying the sidelink controlresource and/or the sidelink data resource. In one embodiment, thesidelink data resource pool may be pre-configured, or may be configuredby base station or network. Furthermore, the sidelink control resourcepool may be pre-configured, or may be configured by basestation/network. In addition, the sidelink feedback resource pool may bepre-configured, or may be configured by base station or network.

In one embodiment, the sidelink data transmission may be unicasttransmission. The data delivered in the sidelink data transmission couldbe for a specific receiving device. The specific receiving device maydeliver feedback information in the feedback transmission on thesidelink feedback resource based on whether data delivered in thesidelink data transmission is decoded successfully or not.

In one embodiment, the transmitting device may monitor or receive thesidelink feedback resources for determining one of at least threepossible feedback information as follows:

-   1. First Feedback Information—The receiving device could receive and    decode the data delivered in the sidelink data transmission    successfully, e.g. ACK;-   2. Second Feedback Information—the receiving device may not decode    the data delivered in the sidelink data transmission successfully,    e.g. NACK; and-   3. Third Feedback Information—the receiving device does not receive    the sidelink control information (successfully), e.g. DTX.

In one embodiment, the transmitting device may determine First FeedbackInformation (discussed above) in response to receiving positiveacknowledgement from the feedback transmission on the sidelink feedbackresource. Furthermore, the transmitting device may determine SecondFeedback Information (discussed above) in response to receivingnon-positive acknowledgement from the feedback transmission on thesidelink feedback resource. In addition, the transmitting device maydetermine Third Feedback Information (discussed above) in response tonot receiving feedback transmission on the sidelink feedback resource.

In one embodiment, the transmitting device may perform sidelink new datatransmission and/or sidelink data retransmission for the receivingdevice depending on the feedback information. Furthermore, thetransmitting device may not perform sidelink data retransmission for thedata delivered in the sidelink data transmission in response to FirstFeedback Information (discussed above). In addition, the transmittingdevice may perform sidelink new data transmission in response to FirstFeedback Information (discussed above). Also, the transmitting devicemay perform sidelink data retransmission for the data delivered in thesidelink data transmission in response to Second Feedback Informationand/or Third Feedback Information.

In one embodiment, the transmitting device may adjust transmissionparameters of sidelink data retransmission and/or sidelink new datatransmission for the receiving device depending on the feedbackinformation. In particular, transmission parameters may comprisemodulation and coding scheme (MCS) and/or transmit power. Thetransmitting device may not set lower MCS in response to the FirstFeedback Information. Furthermore, the transmitting device may notincrease transmit power in response to the First Feeback Information.The transmitting device may set lower MCS in response to the SecondFeedback Information and/or the Third Feedback Information. Thetransmitting device may also increase transmit power in response to theSecond Feedback Information and/or the Third Feedback Information.

In one embodiment, comparing to adjusted MCS in response to feedbackinformation, it may be that adjusted MCS in response to First FeedbackInformation to adjusted MCS in response to Second Feedback Informationadjusted MCS in response Third Feedback Information.

In one embodiment, comparing to adjusted transmit power in response tofeedback information, it may be that adjusted transmit power in responseto First Feedback Information≤adjusted transmit power in response toSecond Feedback Information≤adjusted transmit power in response to ThirdFeedback Information.

In one embodiment, the sidelink data transmission may be groupcastand/or broadcast transmission. The data delivered in the sidelink datatransmission may be received by more than one receiving devices. Inparticular, the data delivered in the sidelink data transmission may befor a set of receiving devices in a same group, and each receivingdevice of the set may transmit feedback transmission on the sidelinkfeedback resource, based on whether data delivered in the sidelink datatransmission is decoded successfully or not. There are three possiblefeedback behaviors as follows:

Feedback Behavior 1—In one embodiment, each receiving device of the setmay deliver positive acknowledgment in feedback transmission on thesidelink feedback resource in response of successful reception ordecoding of data transmission. Furthermore, each receiving device of theset may deliver non-positive acknowledgment in feedback transmission onthe sidelink feedback resource in response of non-successful receptionor decoding of data transmission.

In one embodiment, the transmitting device may monitor/receive theassociated sidelink feedback resource for determining one of at leastthree possible feedback conditions as follows:

-   1. First Feedback Condition—At least part of the set of receiving    devices receives and decodes the data delivered in the sidelink data    transmission successfully, e.g. ACK for at least part of the set of    receiving devices.-   2. Second Feedback Condition—At least part of the set of receiving    devices does not decode the data delivered in the sidelink data    transmission successfully, e.g. NACK for at least part of the set of    receiving devices.-   3. Third Feedback Condition—The set of receiving devices does not    receive the sidelink control information (successfully), e.g. DTX    for the set of receiving devices.

In one embodiment, the transmitting device may determine the FirstFeedback Condition in response to receiving positive acknowledgementfrom the feedback transmission on the sidelink feedback resource.Furthermore, the transmitting device may determine the Second FeedbackCondition in response to receiving non-positive acknowledgement from thefeedback transmission on the sidelink feedback resource. In addition,the transmitting device may determine the Third Feedback Condition inresponse to not receiving feedback transmission on the sidelink feedbackresources.

In one embodiment, the transmitting device may perform sidelink new datatransmission and/or sidelink data retransmission for the receivingdevice depending on the feedback conditions. The transmitting device maynot perform sidelink data retransmission for the data delivered in thesidelink data transmission in response to the First Feedback Condition.However, the transmitting device may perform sidelink new datatransmission in response to the First Feedback Condition. Furthermore,the transmitting device may perform sidelink data retransmission for thedata delivered in the sidelink data transmission in response to theSecond Feedback Condition and/or the Third Feedback Condition.

In one embodiment, the transmitting device may adjust transmissionparameters of sidelink data retransmission and/or sidelink new datatransmission for the receiving device depending on the feedbackconditions. Transmission parameters may comprise any of modulation andcoding scheme (MCS) and/or transmit power. In one embodiment, thetransmitting device may not set lower MCS in response to the FirstFeedback Condition. The transmitting device may not increase transmitpower in response to the First Feedback Condition. The transmittingdevice may set lower MCS in response to the Second Feedback Conditionand/or the Third Feedback Condition. The transmitting device may alsoincrease transmit power in response to the Second Feedback Conditionand/or the Third Feedback Condition.

In one embodiment, comparing to adjusted MCS in response of feedbackconditions, it may be that adjusted MCS in response to the FirstFeedback Condition adjusted MCS in response to the Second FeedbackCondition adjusted MCS in response to the Third Feedback Condition.

In one embodiment, comparing to adjusted transmit power in response offeedback conditions, it may be that adjusted transmit power in responseto the First Feedback Condition≤adjusted transmit power in response tothe Second Feedback Condition≤adjusted transmit power in response to theThird Feedback Condition.

Feedback Behavior 2—In one embodiment, each receiving device of the setmay perform feedback transmission (with positive acknowledgment) on thesidelink feedback resource in response of successful reception ordecoding of data transmission, and does not perform feedbacktransmission on the sidelink feedback resource in response ofnon-successful reception or decoding of data transmission.

In one embodiment, the transmitting device may monitor or receive theassociated sidelink feedback resource for determining one of at leasttwo following possible feedback conditions:

-   1. First Feedback Condition—At least part of the set of receiving    devices receives and decodes the data delivered in the sidelink data    transmission successfully, e.g. ACK for at least part of the set of    receiving devices.-   2. Second Feedback Condition—The set of receiving devices does not    decode the data delivered in the sidelink data transmission    successfully or does not receive the sidelink control information    (successfully), e.g. NACK or DTX for the set of receiving devices.

In one embodiment, the transmitting device may determine the FirstFeedback Condition in response to receiving the feedback transmission(with positive acknowledgement) on the sidelink feedback resource.Furthermore, the transmitting device may determine the Second FeedbackCondition in response to not receiving feedback transmission on thesidelink feedback resources.

In one embodiment, the transmitting device may perform sidelink new datatransmission and/or sidelink data retransmission for the receivingdevice depending on the feedback conditions. The transmitting device maynot perform sidelink data retransmission for the data delivered in thesidelink data transmission in response to the First Feedback Conditionand/or the receiving power of the feedback transmission is larger thanor equal to a threshold. Alternatively, the transmitting device mayperform sidelink new data transmission in response to the First FeedbackCondition and/or the receiving power of the feedback transmission islarger than or equal to a threshold. In addition, the transmittingdevice may perform sidelink data retransmission for the data deliveredin the sidelink data transmission in response to the First FeedbackCondition and/or the receiving power of the feedback transmission islower than or equal to a threshold. Furthermore, the transmitting devicemay perform sidelink data retransmission for the data delivered in thesidelink data transmission in response to the Second Feedback Condition.

In one embodiment, the transmitting device may adjust transmissionparameters of sidelink data retransmission and/or sidelink new datatransmission for the receiving device depending on the feedbackconditions. Transmission parameters may comprise any of modulation andcoding scheme (MCS), and transmit power. The transmitting device may notset lower MCS in response to the First Feedback Condition and/or thereceiving power of the feedback transmission is larger than or equal toa threshold. Furthermore, the transmitting device may not increasetransmit power in response to the First Feedback Condition and/or thereceiving power of the feedback transmission is larger than or equal toa threshold.

In one embodiment, the transmitting device may set lower MCS in responseto the First Feedback Condition and/or the receiving power of thefeedback transmission is lower than or equal to a threshold. Thetransmitting device may also increase transmit power in response to theFirst Feedback Condition and/or the receiving power of the feedbacktransmission is lower than or equal to a threshold. Furthermore, thetransmitting device may set lower MCS in response to the Second FeedbackCondition. The transmitting device may also increase transmit power inresponse to the Second Feedback Condition.

In one embodiment, comparing to adjusted MCS in response of feedbackconditions, it may be that adjusted MCS in response to the FirstFeedback Condition and/or the receiving power of the feedbacktransmission is larger than or equal to a threshold≥adjusted MCS inresponse to the First Feedback Condition and/or the receiving power ofthe feedback transmission is lower than or equal to a threshold≥adjustedMCS in response to the Second Feedback Condition.

In one embodiment, comparing to adjusted transmit power in response offeedback conditions, it may be that adjusted transmit power in responseto the First Feedback Condition and/or the receiving power of thefeedback transmission is larger than or equal to a threshold≤adjustedtransmit power in response to the First Feedback Condition and/or thereceiving power of the feedback transmission is lower than or equal to athreshold≤adjusted transmit power in response to the Second FeedbackCondition.

Feedback Behavior 3—In one embodiment, each receiving device of the setmay perform feedback transmission (with non-positive acknowledgment) onthe sidelink feedback resource in response of non-successful receptionor decoding of data transmission, and does not perform feedbacktransmission on the sidelink feedback resource in response of successfulreception or decoding of data transmission.

In one embodiment, the transmitting device may monitor or receive theassociated sidelink feedback resource for determining one of at leasttwo following possible feedback conditions:

-   1. First Feedback Condition—At least part of the set of receiving    devices does not receive and decode the data delivered in the    sidelink data transmission successfully, e.g. NACK for at least part    of the set of receiving devices.-   2. Second Feedback Condition—The set of receiving devices may decode    the data delivered in the sidelink data transmission successfully,    e.g. ACK for the set of receiving devices.

In one embodiment, the transmitting device may determine the FirstFeedback Condition in response to receiving the feedback transmission(with non-positive acknowledgement) on the sidelink feedback resource.Furthermore, the transmitting device may determine the Second FeedbackCondition in response to not receiving feedback transmission on thesidelink feedback resources.

In one embodiment, the transmitting device may perform sidelink new datatransmission and/or sidelink data retransmission for the receivingdevice depending on the feedback conditions. The transmitting device maynot perform sidelink data retransmission for the data delivered in thesidelink data transmission in response to the Second Feedback Condition.The transmitting device may also perform sidelink new data transmissionfor the data delivered in the sidelink data transmission in response tothe Second Feedback Condition.

In one embodiment, the transmitting device may perform sidelink dataretransmission for the data delivered in the sidelink data transmissionin response to the First Feedback Condition and/or the receiving powerof the feedback transmission is larger than or equal to a threshold. Thetransmitting device may also perform sidelink new data transmission inresponse to the First Feedback Condition and/or the receiving power ofthe feedback transmission is lower than or equal to a threshold.Alternatively, the transmitting device may not perform sidelink dataretransmission for the data delivered in the sidelink data transmissionin response the First Feedback Condition and/or the receiving power ofthe feedback transmission is lower than or equal to a threshold.

In one embodiment, the transmitting device may adjust transmissionparameters of sidelink data retransmission and/or sidelink new datatransmission for the receiving device depending on the feedbackconditions. Transmission parameters may comprise any of modulation andcoding scheme (MCS), and transmit power. The transmitting device may notset lower MCS in response the First Feedback Condition and/or thereceiving power of the feedback transmission is lower than or equal to athreshold. Furthermore, the transmitting device may not increasetransmit power in response the First Feedback Condition and/or thereceiving power of the feedback transmission is lower than or equal to athreshold.

In one embodiment, the transmitting device may set lower MCS in responsethe First Feedback Condition and/or the receiving power of the feedbacktransmission is higher than or equal to a threshold. The transmittingdevice may also increase transmit power in response the First FeedbackCondition and/or the receiving power of the feedback transmission ishigher than or equal to a threshold. Furthermore, the transmittingdevice may not set lower MCS in response to the Second FeedbackCondition. The transmitting device may not increase transmit power inresponse to the Second Feedback Condition.

In one embodiment, comparing to adjusted MCS in response of feedbackconditions, it may be that adjusted MCS in response to the FirstFeedback Condition and/or the receiving power of the feedbacktransmission is larger than or equal to a threshold≤adjusted MCS inresponse to the First Feedback Condition and/or the receiving power ofthe feedback transmission is lower than or equal to a threshold≤adjustedMCS in response to the Second Feedback Condition.

In one embodiment, comparing to adjusted transmit power in response offeedback conditions, it may be that adjusted transmit power in responseto the First Feedback Condition and/or the receiving power of thefeedback transmission is larger than or equal to a threshold≥adjustedtransmit power in response to the First Feedback Condition and/or thereceiving power of the feedback transmission is lower than or equal to athreshold≥adjusted transmit power in response to the Second FeedbackCondition.

II. Method b

The general concept of Method b is that a sidelink feedback resource maybe associated with a sidelink control resource and/or sidelink dataresource. The association may be indicated via a sidelink controlinformation. In one embodiment, the sidelink feedback resource may beindicated via the sidelink control information. A field in the sidelinkcontrol information may indicate the sidelink feedback resource.Furthermore, the sidelink control information may be transmitted on asidelink control resource. The sidelink control information may allocateor indicate a sidelink data resource for a sidelink data transmission.

In one embodiment, the association between the sidelink feedbackresource and the sidelink control resource and/or the sidelink dataresource may be indicated via the sidelink control information. Morespecifically, the sidelink feedback resource may not be derived based onthe sidelink control resource and/or the sidelink data resource. Thesidelink feedback resource may be derived based on indication of thesidelink control information. The sidelink feedback resource may also bederived based on indication of the sidelink control information, thesidelink control resource, and/or the sidelink data resource.

More specifically, when the transmitting device transmits or deliversthe sidelink control information with sidelink feedback resourceindication in sidelink transmission on the sidelink control resource andperforms sidelink data transmission on the sidelink data resource, thetransmitting device may monitor or receive the indicated sidelinkfeedback resource for acquiring feedback information. Furthermore, whenthe receiving device receives the sidelink control information on thesidelink control resource and receives sidelink data transmission on thesidelink data resource, the receiving device may deliver feedbackinformation in feedback transmission on the sidelink feedback resourceindicated by the sidelink control information.

In one embodiment, if the transmitting device performs N sidelink datatransmissions, for delivering the same data, on N sidelink dataresources respectively, the N sidelink control informations forscheduling the N sidelink data transmissions respectively may indicatethe same one sidelink feedback resource. N may be a integer larger thanor equal to one.

If the sidelink data resource and/or the sidelink control resource arescheduled or allocated by base station (e.g. mode 1 in NR V2X and/ormode 3 in LTE V2X), the base station may indicate the sidelink feedbackresource. In one embodiment, the base station may transmit a downlinkcontrol information to indicate the sidelink data resource and/or thesidelink control resource. The downlink control information may indicatethe sidelink feedback resource.

If the sidelink data resource and/or the sidelink control resource aredetermined by device (i.e. base station does not schedule), e.g. mode 2in NR V2X and/or mode 4 in LTE V2X, the transmitting device may performsensing procedure on a sidelink data resource pool for determining thesidelink data resource based on the sensing result of the sidelink dataresource pool. In one embodiment, the transmitting device may performsensing procedure on a sidelink control resource pool for determiningthe sidelink control resource based on the sensing result of thesidelink control resource pool. The transmitting device may also performsensing procedure on a sidelink feedback resource pool for determiningthe sidelink feedback resource based on the sensing result of thesidelink feedback resource pool.

In one embodiment, the receiving device may not perform sensingprocedure on the sidelink feedback resource pool for determining thesidelink feedback resource since the receiving device can derive thesidelink feedback resource based on the sidelink feedback resourceindication in the sidelink control information. In other words, thesidelink feedback transmission resource transmitted by the receivingdevice may be reserved or occupied by the transmitting device. Thetransmitting device may reserve or occupies the sidelink feedbacktransmission resource in response of performing sensing on the sidelinkcontrol resource pool.

In one embodiment, the sidelink data resource pool may be pre-configuredor may be configured by base station or network. The sidelink controlresource pool may also be pre-configured or may be configured by basestation or network. Furthermore, the sidelink feedback resource pool maybe pre-configured or may be configured by base station or network.

III. Method c

The general concept of Method c is that at least two sidelink feedbackresources may be associated with a sidelink control resource and/orsidelink data resource. In one embodiment, one sidelink feedbackresource may be utilized for delivering positive acknowledgment or ACK,and the other sidelink feedback resource may be utilized for deliveringnon-positive acknowledgment or NACK. Furthermore, one sidelink feedbackresource may be utilized to indicate successful reception or decoding ofdata transmission, and the other sidelink feedback resource may beutilized to indicate non-successful reception/decoding of datatransmission.

In one example, the association may be known by devices comprising atransmitting device and a receiving device. The association may be(pre)configured or specified. The at least two sidelink feedbackresources may be derived based on the sidelink control resource and/orthe sidelink data resource. In one embodiment, there may be no explicitindication, in a sidelink control information, for the at least twosidelink feedback resources. Furthermore, there may be no field in thesidelink control information for indicating the at least two sidelinkfeedback resources.

In one example, the association may be indicated via a sidelink controlinformation. In one embodiment, a field in the sidelink controlinformation may indicate the at least two sidelink feedback resources.The sidelink control information may be transmitted on the sidelinkcontrol resource. Furthermore, the sidelink control information mayallocate or indicate the sidelink data resource for a sidelink datatransmission. The at least two sidelink feedback resources may bederived based on indication of the sidelink control information. Inaddition, the at least two sidelink feedback resource may be derivedbased on indication of the sidelink control information, the sidelinkcontrol resource, and/or the sidelink data resource.

More specifically, given the association, when the transmitting devicetransmits or delivers the sidelink control information in sidelinkcontrol transmission on the sidelink control resource and performssidelink data transmission on the sidelink data resource, thetransmitting device may monitor or receive the associated at least twosidelink feedback resources for acquiring feedback information.Furthermore, given the association, when the receiving device receivesthe sidelink control information on the sidelink control resource andreceives the sidelink data transmission on the sidelink data resource,the receiving device may deliver feedback information in feedbacktransmission on one of the associated at least two sidelink feedbackresources, based on whether the sidelink data transmission is decodedsuccessfully or not. In one embodiment, the sidelink control informationmay allocate or indicate the sidelink data resource.

In one embodiment, if the transmitting device performs N sidelink datatransmissions, for delivering the same data, on N sidelink dataresources respectively, there may be N (set) of the associated at leasttwo sidelink feedback resource. N may be an integer larger than or equalto one. In one embodiment, the receiving device may deliver feedbackinformation in feedback transmission(s) in the N associated sidelinkfeedback resources. Furthermore, the receiving device may deliverfeedback information in feedback transmission(s) in part of the N (set)of associated at least two sidelink feedback resources (even though thereceiving device may receive the N sidelink data transmissions).

In one embodiment, if the transmitting device performs N sidelink datatransmissions, for delivering the same data, on N sidelink dataresources respectively, there may be one (set) of the associated atleast two sidelink feedback resource. N may be an integer larger than orequal to one.

In one example, the sidelink data resource and/or the sidelink controlresource may be scheduled/allocated by base station, e.g. mode 1 in NRV2X and/or mode 3 in LTE V2X. The base station may not explicitlyindicate the associated at least two sidelink feedback resources. Thetransmitting device and the receiving device may derive the at least twosidelink feedback resources based on the sidelink control resourceand/or the sidelink data resource. Furthermore, the base station maytransmit a downlink control information to indicate the sidelink dataresource and/or the sidelink control resource. The downlink controlinformation may not indicate the sidelink feedback resource.

In one example, the sidelink data resource and/or the sidelink controlresource may be scheduled or allocated by base station, e.g. mode 1 inNR V2X and/or mode 3 in LTE V2X. The base station may indicate theassociated at least two sidelink feedback resources. Furthermore, thebase station may transmit a downlink control information to indicate thesidelink data resource and/or the sidelink control resource. Thedownlink control information may indicate the at least two sidelinkfeedback resources.

In one example, the sidelink data resource and/or the sidelink controlresource are determined by device (i.e. base station does not schedule),e.g. mode 2 in NR V2X and/or mode 4 in LTE V2X. The transmitting devicemay perform sensing procedure on a sidelink data resource pool fordetermining the sidelink data resource based on the sensing result ofthe sidelink data resource pool. The transmitting device may alsoperform sensing procedure on a sidelink control resource pool fordetermining the sidelink control resource based on the sensing result ofthe sidelink control resource pool.

In one embodiment, the transmitting device does not perform sensingprocedure on a sidelink feedback resource pool for determining theassociated at least two sidelink feedback resources. However, thetransmitting device may perform sensing procedure on a sidelink feedbackresource pool for ensuring the associated at least two feedbackresources are available or clear. Alternatively, the transmitting devicemay perform sensing procedure on a sidelink feedback resource pool fordetermining the at least two sidelink control resources based on thesensing result of the sidelink feedback resource pool. Furthermore, thereceiving device may not perform sensing procedure on the sidelinkfeedback resource pool for determining the at least two sidelinkfeedback resources since the receiving device can derive the at leasttwo sidelink feedback resources based on the sidelink feedback resourceindication in the sidelink control information, and/or the determinedsidelink control resource and/or the determined sidelink data resource.

In other words, the at least two sidelink feedback transmissionresources transmitted by the receiving device may be reserved oroccupied by the transmitting device. The transmitting device may reserveor occupy the sidelink feedback transmission resource in response todetermining or occupying the sidelink control resource and/or thesidelink data resource. Alternatively, the transmitting device mayreserve or occupy the sidelink feedback transmission resource inresponse to performing sensing on the sidelink control resource pool.

In one embodiment, the sidelink data resource pool may be pre-configuredor may be configured by base station or network. Furthermore, thesidelink control resource pool may be pre-configured or may beconfigured by base station or network. In addition, the sidelinkfeedback resource pool may be pre-configured or may be configured bybase station or network.

In one embodiment, the sidelink data transmission may be unicasttransmission. The data delivered in the sidelink data transmission maybe for a specific receiving device. The specific receiving device maytransmit feedback transmission on one of the associated at least twosidelink feedback resources, based on whether data delivered in thesidelink data transmission is decoded successfully or not.

In one embodiment, the transmitting device may monitor or receive theassociated at least two sidelink feedback resources for determining oneof at least three following possible feedback information:

-   1. First Feedback Information—The receiving device receives and    decodes the data delivered in the sidelink data transmission    successfully, e.g. ACK.-   2. Second Feedback Information—The receiving device does not decode    the data delivered in the sidelink data transmission successfully,    e.g. NACK.-   3. Third Feedback Information—The receiving device does not receive    the sidelink control information (successfully), e.g. DTX.

In one embodiment, the transmitting device may determine the FirstFeedback Information in response to receiving feedback transmission onthe first associated sidelink feedback resource (and not receivingfeedback transmission on the second associated sidelink feedbackresource). Furthermore, the transmitting device may determine the SecondFeedback Information in response to receiving feedback transmission onthe second associated sidelink feedback resource (and not receivingfeedback transmission on the first associated sidelink feedbackresource). In addition, the transmitting device may determine the ThirdFeedback Information in response to not receiving feedback transmissionon both of the associated sidelink feedback resources.

In one embodiment, the transmitting device may perform sidelink new datatransmission and/or sidelink data retransmission for the receivingdevice depending on the feedback information. The transmitting devicemay not perform sidelink data retransmission for the data delivered inthe sidelink data transmission in response to the First FeedbackInformation. The transmitting device may perform sidelink new datatransmission in response to the First Feedback Information. Furthermore,the transmitting device may perform sidelink data retransmission for thedata delivered in the sidelink data transmission in response to theSecond Feedback Information and/or the Third Feedback Information.

In one embodiment, the transmitting device may adjust transmissionparameters of sidelink data retransmission and/or sidelink new datatransmission for the receiving device depending on the feedbackinformation. Transmission parameters may comprise any of modulation andcoding scheme (MCS), and transmit power. The transmitting device may notset lower MCS in response to the First Feedback Information. Thetransmitting device may not increase transmit power in response to theFirst Feedback Information. Furthermore, the transmitting device may setlower MCS in response to the Second Feedback Information and/or theThird Feedback Information. The transmitting device may increasetransmit power in response to the Second Feedback Information and/or theThird Feedback Information.

In one embodiment, comparing to adjusted MCS in response to feedbackinformation, it may be that adjusted MCS in response to the FirstFeedback Information≥adjusted MCS in response to the Second FeedbackInformation≥adjusted MCS in response to the Third Feedback Information.

In one embodiment, comparing to adjusted transmit power in response tofeedback information, it may be that adjusted transmit power in responseof to the First Feedback Information≤adjusted transmit power in responseto the Second Feedback Information≤adjusted transmit power in responseto the Third Feedback Information.

In one embodiment, the sidelink data transmission may be groupcastand/or broadcast transmission. The data delivered in the sidelink datatransmission may be received by more than one receiving devices.Furthermore, the data delivered in the sidelink data transmission may befor a set of receiving devices in a same group. Each receiving device ofthe set may transmit feedback transmission on one of the associatedfeedback resources, based on whether data delivered in the sidelink datatransmission is decoded successfully or not.

In one embodiment, the transmitting device may monitor or receive theassociated at least two sidelink feedback resources for determining oneof at least four following possible feedback conditions:

-   1. First Feedback Condition—The set of receiving devices receives    and decodes the data delivered in the sidelink data transmission    successfully, e.g. ACK for (all) the set of receiving devices.-   2. Second Feedback Condition—The set of receiving devices does not    decode the data delivered in the sidelink data transmission    successfully, e.g. NACK for (all) the set of receiving devices.-   3. Third Feedback Condition—Part of the set of receiving devices    receives and decodes the data delivered in the sidelink data    transmission successfully and part of the set of receiving devices    does not decode the data delivered in the sidelink data transmission    successfully, e.g. ACK for part the set of receiving devices and    NACK for part of the set of receiving devices.-   4. Fourth Feedback Condition—The set of receiving devices does not    receive the sidelink control information (successfully), e.g. DTX    for (all) the set of receiving devices.

In one embodiment, the transmitting device may determine the FirstFeedback Condition in response to receiving feedback transmission on thefirst associated sidelink feedback resource and not receiving feedbacktransmission on the second sidelink feedback resource. Furthermore, thetransmitting device may determine the Second Feedback Condition inresponse of receiving feedback transmission on the second associatedsidelink feedback resource and not receiving feedback transmission onthe first associated sidelink feedback resource. In addition, thetransmitting device may determine the Third Feedback Condition inresponse to receiving feedback transmission on both associated sidelinkfeedback resources. Also, the transmitting device may determine theFourth Feedback Condition in response to not receiving feedbacktransmission on both associated two sidelink feedback resources.

In one embodiment, the transmitting device may perform sidelink new datatransmission and/or sidelink data retransmission for the set of thereceiving devices depending on the feedback condition. The transmittingdevice may not perform sidelink data retransmission for the datadelivered in the sidelink data transmission in response to the FirstFeedback Condition. The transmitting device may perform sidelink newdata transmission in response to the First Feedback Condition.Furthermore, the transmitting device may perform sidelink dataretransmission for the data delivered in the sidelink data transmissionin response to the First Feedback Condition, the Second FeedbackCondition, the Third Feedback Condition, and/or the to the FourthFeedback Condition. In addition, the transmitting device may performsidelink data retransmission for the data delivered in the sidelink datatransmission in response to the Second Feedback Condition and/or theFourth Feedback Condition. Also, the transmitting device may performsidelink data retransmission for the data delivered in the sidelink datatransmission in response to the Third Feedback Condition if thetransmitting device detects that the receiving power on the firstassociated sidelink feedback resource is smaller than or equal to thereceiving power on the second associated sidelink feedback resource.Additionally, the transmitting device may not perform sidelink dataretransmission for the data delivered in the sidelink data transmissionin response to the Third Feedback Condition if the transmitting devicedetects that the receiving power on the first associated sidelinkfeedback resource is larger than or equal to the receiving power on thesecond associated sidelink feedback resource.

In one embodiment, the transmitting device may adjust transmissionparameters of sidelink data retransmission and/or sidelink new datatransmission for the set of the receiving devices depending on thefeedback condition. Transmission parameters may comprise any ofmodulation and coding scheme (MCS), and transmit power. In oneembodiment, the transmitting device may not set lower MCS in response tothe First Feedback Condition. The transmitting device may not increasetransmit power in response to the First Feedback Condition. Furthermore,the transmitting device may set lower MCS in response to the SecondFeedback Condition and/or the Fourth Feedback Condition. Thetransmitting device may also increase transmit power in response to theSecond Feedback Condition and/or the Fourth Feedback Condition.Furthermore, the transmitting device may lower the MCS in response tothe Third Feedback Condition. The degree or level of lowered MCS may bedepending on the receiving power difference between the feedbacktransmissions on the first and second associated sidelink feedbackresources. In addition, the transmitting device may increase transmitpower in response to the Third Feedback Condition. The degree/level ofincreased transmit power may depend on the receiving power differencesbetween the feedback transmissions on the first and second associatedsidelink feedback resources.

In one embodiment, comparing to adjusted MCS in response of feedbackconditions, it may be that adjusted MCS in response to the FirstFeedback Condition adjusted MCS in response to the Third FeedbackCondition with higher receiving power on the first associated sidelinkfeedback resource≥adjusted MCS in response to the Third FeedbackCondition with higher receiving power on the second associated sidelinkfeedback resource≥adjusted MCS in response to the Second FeedbackCondition adjusted MCS in response to the Fourth Feedback Condition.

In one embodiment, comparing to adjusted transmit power in response offeedback conditions, it may be that adjusted transmit power in responsethe First Feedback Condition≤adjusted transmit power in response to theThird Feedback Condition with higher receiving power on the firstassociated sidelink feedback resource≤adjusted transmit power inresponse to the Third Feedback Condition with higher receiving power onthe second associated sidelink feedback resource≤adjusted transmit powerin response to the Second Feedback Condition≤adjusted transmit power inresponse to the Fourth Feedback Condition.

IV. Method d

The general concept of Method d is that multiple sidelink feedbackresources may be associated with a sidelink control resource and/orsidelink data resource. Each sidelink feedback resource may be utilizedby a receiving device for delivering feedback information. In oneembodiment, different receiving devices may utilize different sidelinkfeedback resources for delivering feedback information. A receivingdevice may deliver positive acknowledgment or ACK to indicate successfulreception or decoding of the sidelink data transmission. Furthermore,the receiving device may deliver non-positive acknowledgment or NACK toindicate non-successful reception or decoding of the sidelink datatransmission.

In one example, the association may be known by devices comprising atransmitting device and multiple receiving devices. The association maybe (pre)configured or specified. In one embodiment, the multiplesidelink feedback resources may be derived based on the sidelink controlresource and/or the sidelink data resource. Furthermore, the multiplesidelink feedback resources may be derived based on the sidelink controlresource, the sidelink data resource, and/or an identity of thereceiving device. There may be no explicit indication, in a sidelinkcontrol information, for indicating sidelink feedback resource. Also,there may be no field in the sidelink control information for indicatingsidelink feedback resource.

In one example, the association may be indicated via a sidelink controlinformation. A field in the sidelink control information may indicatethe sidelink feedback resource. The sidelink control information may betransmitted on the sidelink control resource. Furthermore, the sidelinkcontrol information may allocate or indicate the sidelink data resourcefor a sidelink data transmission. In addition, the sidelink feedbackresource may be derived based on indication of the sidelink controlinformation. Also, the sidelink feedback resource may be derived basedon indication of the sidelink control information and/or an identity ofthe receiving device.

In one embodiment, the resource may be derived based on indication ofthe sidelink control information, the sidelink control resource, and/orthe sidelink data resource. The resource may also be derived based onindication of the sidelink control information, the sidelink controlresource, the sidelink data resource, and/or an identity of thereceiving device.

More specifically, given the association, when the transmitting devicetransmits or delivers the sidelink control information in sidelinkcontrol transmission on the sidelink control resource and performssidelink data transmission on the sidelink data resource, thetransmitting device could monitor or receive the associated multiplesidelink feedback resources for acquiring feedback information frommultiple receiving devices. In one embodiment, the feedback informationdelivered in feedback transmission in an associated sidelink feedbackresource may reflect whether the sidelink data transmission is decodedsuccessfully or not by a receiving device. The feedback informationdelivered in feedback transmission in two distinct sidelink feedbackresources may reflect whether the sidelink data transmission is decodedsuccessfully or not by two distinct receiving devices. Morespecifically, given the association, when the receiving device receivesthe sidelink control information on the sidelink control resource andreceives the sidelink data transmission on the sidelink data resource,the receiving device may deliver feedback information in feedbacktransmission on an associated sidelink feedback resource, based onwhether the sidelink data transmission is decoded successfully or not bythe receiving device. In one embodiment, the sidelink controlinformation may allocate or indicate the sidelink data resource.

In one embodiment, if the transmitting device performs N sidelink datatransmissions, for delivering the same data, on N sidelink dataresources respectively, there may be N (set) of sidelink feedbackresources. N may be a integer larger than or equal to one. In oneembodiment, the receiving device may deliver feedback information infeedback transmission(s) in N sidelink feedback resources, wherein eachone of the N sidelink feedback resources is within one of the N (set) ofth associated sidelink feedback resources. The receiving device maydeliver feedback information in feedback transmission(s) in part of theN sidelink feedback resources (even though the receiving device mayreceive the N sidelink data transmissions).

In one embodiment, if the transmitting device performs N sidelink datatransmissions, for delivering the same data, on N sidelink dataresources respectively, there may be one (set) of associated sidelinkfeedback resources. N may be a integer larger than or equal to one.

In one example, the sidelink data resource and/or the sidelink controlresource may be scheduled or allocated by base station, e.g. mode 1 inNR V2X and/or mode 3 in LTE V2X. In one embodiment, the base station maynot explicitly indicate the associated multiple sidelink feedbackresources. The transmitting device and the receiving device may derivethe multiple sidelink feedback resources based on the sidelink controlresource and/or the sidelink data resource. The base station maytransmit a downlink control information to indicate the sidelink dataresource and/or the sidelink control resource. The downlink controlinformation may not indicate the sidelink feedback resource.

In one example, the sidelink data resource and/or the sidelink controlresource may be scheduled or allocated by base station, e.g. mode 1 inNR V2X and/or mode 3 in LTE V2X. In one embodiment, the base station mayindicate the associated multiple sidelink feedback resources. The basestation may also transmit a downlink control information to indicate thesidelink data resource and/or the sidelink control resource. Thedownlink control information may indicate the multiple sidelink feedbackresources.

In one example, the sidelink data resource and/or the sidelink controlresource may be determined by device (i.e. base station does notschedule), e.g. mode 2 in NR V2X and/or mode 4 in LTE V2X. Thetransmitting device may perform sensing procedure on a sidelink dataresource pool for determining the sidelink data resource based on thesensing result of the sidelink data resource pool. The transmittingdevice may perform sensing procedure on a sidelink control resource poolfor determining the sidelink control resource based on the sensingresult of the sidelink control resource pool. The transmitting devicemay not perform sensing procedure on a sidelink feedback resource poolfor determining the sidelink feedback resources. Furthermore, thetransmitting device may perform sensing procedure on a sidelink feedbackresource pool for ensuring the multiple feedback resources are availableor clear. Alternatively, the transmitting device may perform sensingprocedure on a sidelink feedback resource pool for determining thesidelink control resources based on the sensing result of the sidelinkfeedback resource pool. The receiving device may not perform sensingprocedure on the sidelink feedback resource pool for determining theassociated sidelink feedback resource since the receiving device canderive the sidelink feedback resource based on the sidelink feedbackresource indication in the sidelink control information, the determinedsidelink control resource, the determined sidelink data resource, and/orthe identity of the receiving device. In other words, the sidelinkfeedback transmission resources transmitted by the multiple receivingdevices could be reserved or occupied by the transmitting device. Thetransmitting device may reserve or occupy the sidelink feedbacktransmission resources in response of determining or occupying thesidelink control resource and/or the sidelink data resource.

Alternatively, the transmitting device may reserve or occupy thesidelink feedback transmission resources in response of performingsensing on the sidelink control resource pool. The sidelink dataresource pool may be pre-configured or may be configured by base stationor network. Furthermore, the sidelink control resource pool may bepre-configured and may be configured by base station or network. Inaddition, the sidelink feedback resource pool may be pre-configured ormay be configured by base station or network.

In one embodiment, the sidelink data transmission may be groupcastand/or broadcast transmission. The data delivered in the sidelink datatransmission may be received by more than one receiving devices.Furthermore, the data delivered in the sidelink data transmission may befor a set of receiving devices in a same group. Each receiving device ofthe set may transmit feedback transmission on one of the multiplesidelink feedback resources, based on whether data delivered in thesidelink data transmission is decoded successfully or not by thereceiving device. The transmitting device may monitor or receive themultiple sidelink feedback resources for acquire the feedbackinformation of the receiving devices. Furthermore, the transmittingdevice may monitor or receive one of the multiple sidelink feedbackresources for acquire the feedback information of one of the receivingdevices.

In one embodiment, the transmitting device may monitor or receive thesidelink feedback resources for determining one of at least threefollowing possible feedback information for each sidelink feedbackresource:

-   1. First Feedback Information—The receiving device receives and    decodes the data delivered in the sidelink data transmission    successfully, e.g. ACK.-   2. Second Feedback Information—The receiving device does not decode    the data delivered in the sidelink data transmission successfully,    e.g. NACK.-   3. Third Feedback Information—The receiving device does not receive    the sidelink control information (successfully), e.g. DTX.

In one embodiment, the transmitting device may determine the FirstFeedback Information in response to receiving feedback transmission onone of the sidelink feedback resources. Furthermore, the transmittingdevice may determine the Second Feedback Information in response toreceiving feedback transmission on one of the sidelink feedbackresources. In addition, the transmitting device may determine the ThirdFeedback Information in response to not receiving feedback transmissionon one of the sidelink feedback resources.

In one embodiment, the transmitting device may perform sidelink new datatransmission and/or sidelink data retransmission for the receivingdevices depending on the feedback information. The transmitting devicemay not perform sidelink data retransmission for the data delivered inthe sidelink data transmission in response to the First FeedbackInformation. The transmitting device may perform sidelink new datatransmission in response to the First Feedback Information. Furthermore,the transmitting device may perform sidelink data retransmission for thedata delivered in the sidelink data transmission to a receiving devicein response to the First Feedback Information of the receiving device.In one embodiment, the sidelink data retransmission may be groupcastand/or broadcast transmission.

In one embodiment, the transmitting device may perform sidelink dataretransmission for the data delivered in the sidelink data transmissionin response to the Second Feedback Information and/or the Third FeedbackInformation. In addition, the transmitting device may perform sidelinkdata retransmission for the data delivered in the sidelink datatransmission to a receiving device in response to the Second FeedbackInformation and/or the Third Feedback Information of the receivingdevice. In one embodiment, the sidelink data retransmission may beunicast transmission to the receiving device. Furthermore, the sidelinkdata retransmission may be groupcast and/or broadcast transmission. Inone embodiment, the transmitting device may perform sidelink new datatransmission and/or sidelink data retransmission for the receivingdevices if feedback transmission on at least a ratio or a number offeedback resources delivers the Second Feedback Information and/or theThird Feedback Information.

For instance, there are 11 devices in a same group. When a transmittingdevice transmits or delivers a sidelink control information in sidelinkcontrol transmission on a sidelink control resource and performs asidelink data transmission on the sidelink data resource, thetransmitting device could monitor or receive the associated 10 sidelinkfeedback resources for acquiring feedback information from the 10receiving devices. The transmission device and the 10 receiving devicescould be in the same group.

If the transmitting device monitors or receives the 10 sidelink feedbackresources and acquires 6 NACK and/or DTX, the transmitting device mayperform sidelink data retransmission. Furthermore, if the transmittingdevice monitors or receives the 10 sidelink feedback resources andacquires 2 NACK and/or DTX, the transmitting device may not performsidelink data retransmission and may perform sidelink new datatransmission. If the transmitting device monitors or receives the 10sidelink feedback resources and acquires 4 ACKs, the transmitting devicemay perform sidelink data retransmission. Furthermore, if thetransmitting device monitors/receives the 10 sidelink feedback resourcesand acquires 8 ACKs, the transmitting device may not perform sidelinkdata retransmission and may perform sidelink new data transmission.

In one embodiment, the transmitting device may adjust transmissionparameters of sidelink data retransmission and/or sidelink new datatransmission for the receiving device depending on the feedbackinformation. Transmission parameters may comprise any of modulation andcoding scheme (MCS), and transmit power. The transmitting device may notset lower MCS in response to the First Feedback Information. Thetransmitting device may not increase transmit power in response to theFirst Feedback Information. Furthermore, the transmitting device may setlower MCS in response to the Second Feedback Information and/or theThird Feedback Information. The transmitting device may increasetransmit power in response to the Second Feedback Information and/or theThird Feedback Information.

In one embodiment, the transmitting device may adjust transmissionparameters of sidelink data retransmission and/or sidelink new datatransmission for the multiple receiving devices if feedback transmissionon at least a ratio or a number of feedback resources delivers theSecond Feedback Information and/or the Third Feedback Information. Ifthere are more Second Feedback Information and/or Third FeedbackInformation, a lower MCS and/or a higher transmit power may be set. Ifthere are less First Feedback Information, a lower MCS and/or a highertransmit power may be set.

For instance, there are 11 devices in a same group. When a transmittingdevice transmits or delivers a sidelink control information in sidelinkcontrol transmission on a sidelink control resource and performs asidelink data transmission on the sidelink data resource, thetransmitting device could monitor or receive the associated 10 sidelinkfeedback resources for acquiring feedback information from the 10receiving devices. The transmission device and the 10 receiving devicescould be in the same group.

If the transmitting device monitors or receives the 10 sidelink feedbackresources and acquires 6 NACK and/or DTX, the transmitting device maylower the MCS by 2 levels or increase the transmit power by 5 dB. If thetransmitting device monitors or receives the 10 sidelink feedbackresources and acquires 2 NACK and/or DTX, the transmitting device maylower the MCS by 1 level or increase the transmit power by 3 dB. If thetransmitting device monitors or receives the 10 sidelink feedbackresources and acquires 0 NACK and/or DTX, the transmitting device maynot adjust MCS or may not increase transmit power. If the transmittingdevice monitors/receives the 10 sidelink feedback resources and acquires4 ACKs, the transmitting device may lower the MCS by 2 levels orincrease the transmit power by 5 dB. If the transmitting device monitorsor receives the 10 sidelink feedback resources and acquires 8 ACKs, thetransmitting device may lower the MCS by 1 level or increase thetransmit power by 3 dB. If the transmitting device monitors or receivesthe 10 sidelink feedback resources and acquires 10 ACKs, thetransmitting device may not adjust MCS or may not increase transmitpower.

V. Applicable to all Methods and Embodiments Discussed Above

The association between a sidelink feedback resource and a sidelinkcontrol resource may mean a fixed or configured or specified timedifference (in TTI units) between the sidelink feedback resource and thesidelink control resource. Furthermore, the association between asidelink feedback resource and a sidelink data resource may mean a fixedor configured or specified time difference (in TTI units) between thesidelink feedback resource and the sidelink data resource. In addition,the association between a sidelink feedback resource and an indicationof a sidelink control information may mean the time difference (in TTIunits) between the sidelink feedback resource and the sidelink controlresource is indicated by the indication of the sidelink controlinformation. Also, the sidelink feedback resource derived based onindication of the sidelink control information may mean that the timedifference (in TTI units) between the sidelink feedback resource and thesidelink control resource is indicated by the indication of the sidelinkcontrol information.

In one embodiment, the association between a sidelink feedback resourceand an indication of a sidelink control information may mean the timedifference, (in TTI units) between the sidelink feedback resource andthe sidelink data resource could be indicated by the sidelink controlinformation. The sidelink feedback resource derived based on indicationof the sidelink control information may mean that the time difference(in TTI units) between the sidelink feedback resource and the sidelinkdata resource could be indicated by the sidelink control information.The sidelink feedback resource derived based on an identity of thereceiving device may mean that the time difference (in TTI units)between the sidelink feedback resource and the sidelink control resourcecould be indicated or derived by the identity of the receiving device.In one embodiment, the TTI may mean slot, mini-slot, subframe, symbol, aset of symbols, or mini-seconds.

In one embodiment, the association between a sidelink feedback resourceand a sidelink control resource may mean a fixed or configured orspecified frequency resource (index) difference (in frequency resourceunits) between the sidelink feedback resource and the sidelink controlresource. Furthermore, the association between a sidelink feedbackresource and a sidelink data resource may mean a fixed or configured orspecified frequency resource (index) difference (in frequency resourceunits) between the sidelink feedback resource and the sidelink dataresource. In addition, the association between a sidelink feedbackresource and an indication of a sidelink control information may meanthe frequency resource (index) difference (in frequency resource units)between the sidelink feedback resource and the sidelink control resourceis indicated by the sidelink control information. In one embodiment, thesidelink feedback resource derived based on indication of the sidelinkcontrol information may mean that the frequency resource (index)difference (in frequency resource units) between the sidelink feedbackresource and the sidelink control resource is indicated by the sidelinkcontrol information.

In one embodiment, the association between a sidelink feedback resourceand an indication of a sidelink control information may mean thefrequency resource (index) difference (in frequency resource units)between the sidelink feedback resource and the sidelink data resource isindicated by the sidelink control information. Furthermore, the sidelinkfeedback resource derived based on indication of the sidelink controlinformation may mean that the frequency resource (index) difference (infrequency resource units) between the sidelink feedback resource and thesidelink data resource is indicated by the sidelink control information.

In one embodiment, the sidelink feedback resource derived based on anidentity of the receiving device may mean that the frequency resource(index) difference (in frequency resource units) between the sidelinkfeedback resource and the sidelink control resource is indicated orderived by the identity of the receiving device. Furthermore, thesidelink feedback resource derived based on an identity of the receivingdevice may mean that the frequency resource (index) difference (infrequency resource units) between the sidelink feedback resource and thesidelink data resource is indicated or derived by the identity of thereceiving device. In one embodiment, the frequency resource unit may bea subchannel, a (physical) resource element, a (physical) resourceblock, or a set of (physical) resource blocks.

In one embodiment, the association between a sidelink feedback resourceand a sidelink control resource may mean a fixed or configured orspecified resource (index) difference between a sidelink feedbackresource index and the sidelink control resource index. Furthermore, theassociation between a sidelink feedback resource and a sidelink dataresource may mean a fixed or configured or specified resource (index)difference between the sidelink feedback resource index and the sidelinkdata resource index. In addition, the association between a sidelinkfeedback resource and an indication of a sidelink control informationmay mean the resource (index) difference between the sidelink feedbackresource index and the sidelink control resource index is indicated bythe sidelink control information. In one embodiment, the sidelinkfeedback resource derived based on indication of the sidelink controlinformation may mean that the resource (index) difference between thesidelink feedback resource index and the sidelink control resource indexis indicated by the sidelink control information.

In one embodiment, the association between a sidelink feedback resourceand an indication of a sidelink control information may mean theresource (index) difference between the sidelink feedback resource indexand the sidelink data resource index is indicated by the sidelinkcontrol information. Furthermore, the sidelink feedback resource derivedbased on indication of the sidelink control information may mean thatthe resource (index) difference between the sidelink feedback resourceindex and the sidelink data resource index is indicated by the sidelinkcontrol information.

In one embodiment, the association between a sidelink feedback resourceand an indication of a sidelink control information may mean thesidelink control information indicates the resource (index) of thesidelink feedback resource. The sidelink feedback resource derived basedon indication of the sidelink control information may mean the sidelinkcontrol information indicates the resource (index) of the sidelinkfeedback resource.

In one embodiment, the sidelink feedback resource derived based on anidentity of the receiving device may mean that the resource (index)difference between the sidelink feedback resource index and the sidelinkcontrol resource index is indicated or derived by the identity of thereceiving device. Furthermore, the sidelink feedback resource derivedbased on an identity of the receiving device may mean that the resource(index) difference between the sidelink feedback resource index and thesidelink data resource index is indicated or derived by the identity ofthe receiving device.

In one embodiment, the sidelink data resource index may mean subchannelindex. The subchannel index could be the index of the lowest subchannelcomprised in the sidelink data resource. Furthermore, the sidelink dataresource index may mean resource block index. The resource block indexcould be the index of the lowest resource block comprised in thesidelink data resource.

In one embodiment, the sidelink control resource index may meansubchannel index. The subchannel index could be the index of the lowestsubchannel comprised in the sidelink control resource. The subchannelindex could also be the index of the subchannel comprising the sidelinkcontrol resource.

In one embodiment, the sidelink control resource index may mean resourceblock index. The resource block index could be the index of the lowestresource block comprised in the sidelink control resource. The resourceblock index could also be the index of the resource block comprising thesidelink control resource. Alternatively, the sidelink control resourceindex may mean CCE index. The resource block index could be the index ofthe lowest CCE comprised in the sidelink control resource.

In one embodiment, the sidelink feedback resource index may meansubchannel index. The subchannel index could be the index of the lowestsubchannel comprised in the sidelink feedback resource. The block indexcould the index of the subchannel comprising the sidelink feedbackresource. Alternatively, the sidelink feedback resource index may meanresource block index. The resource block index could be the index of thelowest resource block comprised in the sidelink feedback resource. Theresource block index could also be the index of the resource blockcomprising the sidelink feedback resource.

In one embodiment, the identity of the receiving device may meandestination identity. The identity of the receiving device may beutilized to indicate which receiving device receives the sidelinkcontrol or data information. Furthermore, the identity of the receivingdevice may be an offset or a value configured for the receiving device.In addition, the identity of the receiving device may be utilized forderiving sidelink feedback resource.

In one embodiment, the transmitting device may perform sensing procedureon a sidelink feedback resource pool for determining the sidelinkfeedback resource may mean that the transmitting device may performsensing procedure on a candidate set of sidelink feedback resources inthe sidelink feedback resource pool for determining the sidelinkfeedback resource. The candidate set of sidelink feedback resources maybe determined or derived based on the associated sidelink controlresource and/or sidelink data resource. Furthermore, the candidate setof sidelink feedback resources may comprise a fixed or configure orspecified number of sidelink feedback resources. More specifically, thecandidate set of sidelink feedback resources may comprise 4 or 6 or 8sidelink feedback resources.

In one embodiment, successful reception or decoding of the sidelink datatransmission may mean that the CRC check of the sidelink datatransmission is passed. Non-successful reception or decoding of thesidelink data transmission may mean that the CRC check of the sidelinkdata transmission is not passed.

In one embodiment, the data may mean a MAC PDU or a data packet.Furthermore, the data may be delivered on SL-SCH. However, the data maynot be delivered on DL-SCH or UL-SCH. In addition, the data may betransmitted on PSSCH. However, the data may not be transmitted on PDSCHor PUSCH.

In one embodiment, the sidelink feedback transmission may mean PSCCH.Furthermore, the sidelink data transmission may mean PSSCH. In addition,the sidelink control information may mean neither downlink controlinformation nor uplink control information. The sidelink controlinformation may be transmitted or delivered on PSCCH. However, thesidelink control information may not be transmitted or delivered onPDCCH or PUCCH. In one embodiment, the sidelink control transmission maymean PSCCH. The sidelink control transmission may not be transmitted onPDCCH or PUCCH.

In one embodiment, the sensing procedure may comprise the devicereceiving a transmission, and the device excluding the (time andfrequency) candidate resources associated with the receivedtransmission. The excluded candidate resources associated with thereceived transmission may mean that the candidate resources are expectedto be utilized by a device which transmits the received transmission.

In one embodiment, the sensing procedure may comprise the deviceperforming energy sensing to derive metric for candidate resources. Thedevice may exclude the candidate resources with larger metric. Thedevice may select the candidate resources with smaller metric as validcandidate resources. The candidate resources with larger metric may meanthe metric of the candidate resources is larger than metric of apercentage of total candidate resources. The candidate resources withsmaller metric may mean the metric of the candidate resources is smallerthan metric of a percentage of total candidate resources.

In one embodiment, the energy sensing may mean that the device performsRSSI measurement. The metric may mean a RSSI or a linear average ofmeasured RSSI. The metric for a candidate resource may mean a linearaverage of RSSI measured from associated resources of the candidateresource.

In one embodiment, the sidelink control, data, or feedback transmissionor reception may be device-to-device transmission or reception, V2Xtransmission or reception, or P2X transmission or reception.Furthermore, the sidelink control, data, or feedback transmission orreception may be on PC5 interface.

In one embodiment, the PC5 interface may be wireless interface forcommunication between device and device, wireless interface forcommunication between devices, wireless interface for communicationbetween UEs, or wireless interface for V2X or P2X communication. The Uuinterface may be wireless interface for communication between networknode and device, or wireless interface for communication between networknode and UE.

In one embodiment, the device may be a UE. The device may also be avehicle UE or a V2X UE. The base station may be a network node, anetwork node type RSU, or a gNB. The MCS may reflect coding rate. Alower MCS may mean lower coding rate.

FIG. 14 is a flow chart 1400 according to one exemplary embodiment fromthe perspective of a first device. In step 1405, the first deviceperforms sensing on a data resource pool. In step 1410, the first deviceselects or derives at least a first data resource from the data resourcepool based on the sensing result of the data resource pool. In step1415, the first device transmits a first control information on a firstcontrol resource, wherein the first control information allocates orindicates the first data resource. In step 1420, the first deviceperforms a first data transmission on the first data resource to atleast one second device. In step 1425, the first device determines orderives a first set of feedback resource(s) based on the first controlresource and/or the first data resource. In step 1430, the first devicereceives a first set of feedback transmission(s) on the first set offeedback resource(s) from at least the one second device, wherein thefirst set of feedback transmissions are associated with the first datatransmission.

In one embodiment, for determining or deriving the first set of feedbackresource(s), the first device may not perform sensing on a candidate setof feedback resources, wherein the candidate set of feedback resourcescomprises the first set of feedback resource(s). The first device coulddetermine or derive the first set of feedback resource(s) from thecandidate set of feedback resources without basing on sensing result ofthe candidate set of feedback resources.

In one embodiment, when the first data transmission is unicasttransmission (to a second device), the first set of feedback resource(s)may mean a first feedback resource, and the first set of feedbacktransmission(s) may mean a first feedback transmission. The first devicecould determine or derive the first feedback resource based on the firstcontrol resource, the first data resource, and/or an identity of thesecond device.

In one embodiment, when the first data transmission is groupcasttransmission (to a sidelink group comprising at least the seconddevice), (each) one of the first set of feedback transmissions, on(each) one of the first set of feedback resources, delivers feedbackinformation from one device (within the sidelink group). The firstdevice could determine or derive (each) one of the first set of feedbackresources, based on the first control resource, the first data resource,and/or an identity of (each) one device (within the sidelink group).

In one embodiment, the resource association, in time domain and/orfrequency domain, between the first set of feedback resource(s) and thefirst control resource, and/or the first data resource could be(pre)configured or specified. The first control information may includeno field for indicating the first set of feedback resource(s).

In one embodiment, the first device could receive a second controlinformation on a second control resource, wherein the second controlinformation allocates or indicates a second data resource. The firstdevice could also receive a second data transmission on the second dataresource. Furthermore, the first device could determine or derive asecond feedback resource based on the second control resource and/or thesecond data resource. In addition, the first device could transmit asecond feedback transmission associated to the second data transmissionon the second feedback resource.

In one embodiment, for determining or deriving the second feedbackresource, the first device may not perform sensing on a candidate set offeedback resources, wherein the candidate set of feedback resourcescomprises the second feedback resource. However, the first device maydetermine or derive the second feedback resource from the candidate setof feedback resources without basing on sensing result of the candidateset of feedback resources.

In one embodiment, the resource association, in time domain and/orfrequency domain, between the second feedback resource and the secondcontrol resource, and/or the second data resource may be (pre)configuredor specified. The second control information may include no field forindicating the second feedback resource.

In one embodiment, the first device could determine or derive the secondfeedback resource based on the second control resource, the second dataresource, and/or an identity of the first device. The candidate set offeedback resources may comprise the first set of feedback resource(s)and the second feedback resource; and the data resource pool maycomprise the first data resource and the second data resource.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of a firstdevice, the device 300 includes a program code 312 stored in the memory310. The CPU 308 could execute program code 312 to enable the firstdevice (i) to perform sensing on a data resource pool, (ii) to select orderive at least a first data resource from the data resource pool basedon the sensing result of the data resource pool, (iii) to transmit afirst control information on a first control resource, wherein the firstcontrol information allocates or indicates the first data resource, (iv)to perform a first data transmission on the first data resource to atleast one second device, (v) to determine or derive a first set offeedback resource(s) based on the first control resource and/or thefirst data resource, and (vi) to receive a first set of feedbacktransmission(s) on the first set of feedback resource(s) from at leastthe one second device, wherein the first set of feedback transmissionsare associated with the first data transmission. Furthermore, the CPU308 can execute the program code 312 to perform all of theabove-described actions and steps or others described herein.

FIG. 15 is a flow chart 1500 according to one exemplary embodiment fromthe perspective of a first device. In step 1505, the first devicetransmits a third control information on a third control resource,wherein the third control information schedules or indicates a thirddata resource. In step 1510, the first device performs a third datatransmission on the third data resource. In step 1515, the first devicedetermines or derives a third feedback resource and a fourth feedbackresource based on the third control resource and/or the third dataresource. In step 1520, the first device detects or receives the thirdfeedback resource and the fourth feedback resource, wherein the thirdfeedback resource is utilized for delivering HARQ acknowledgement, andthe fourth feedback resource is utilized for delivering HARQnon-acknowledgement.

In one embodiment, the third feedback resource and the fourth feedbackresource may be different in frequency domain, and/or the third feedbackresource and the fourth feedback resource may be in the same TTI orsymbol. Furthermore, for determining or deriving the third feedbackresource and the fourth feedback resource, the first device may notperform sensing on a candidate set of feedback resources, wherein thecandidate set of feedback resources comprises the third feedbackresource and the fourth feedback resource. In addition, the first devicecould determine or derive the third feedback resource and the fourthfeedback resource from the candidate set of feedback resources withoutbasing on sensing result of the candidate set of feedback resources.

In one embodiment, the resource association, in time domain and/orfrequency domain, between the third feedback resource and the thirdcontrol resource, and/or the third data resource may be (pre)configuredor specified. Furthermore, the resource association, in time domainand/or frequency domain, between the fourth feedback resource and thethird control resource, and/or the third data resource may be(pre)configured or specified.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of a firstdevice, the device 300 includes a program code 312 stored in the memory310. The CPU 308 could execute program code 312 to enable the firstdevice (i) to transmit a third control information on a third controlresource, wherein the third control information schedules or indicates athird data resource, (ii) to perform a third data transmission on thethird data resource, (iii) to determine or derive a third feedbackresource and a fourth feedback resource based on the third controlresource and/or the third data resource, and (iv) to detect or receivethe third feedback resource and the fourth feedback resource, whereinthe third feedback resource is utilized for delivering HARQacknowledgement, and the fourth feedback resource is utilized fordelivering HARQ non-acknowledgement. Furthermore, the CPU 308 canexecute the program code 312 to perform all of the above-describedactions and steps or others described herein.

FIG. 16 is a flow chart 1600 according to one exemplary embodiment fromthe perspective of a second device. In step 1605, the second devicereceives a third control information on a third control resource,wherein the third control information schedules or indicates a thirddata resource. In step 1610, the second device receives a third datatransmission on the third data resource. In step 1615, the second devicedetermines or derives a third feedback resource and a fourth feedbackresource based on the third control resource and/or the third dataresource. In step 1620, if the second device receives or decodes thethird data transmission successfully, the second device transmits HARQacknowledgement on the third feedback resource. In step 1625, if thesecond device does not receive or decode the third data transmissionsuccessfully, the second device transmits HARQ non-acknowledgement onthe fourth feedback resource.

In one embodiment, the resource association, in time domain and/orfrequency domain, between the third feedback resource, the third controlresource, and/or the third data resource may be (pre)configured orspecified. Furthermore, the resource association, in time domain and/orfrequency domain, between the fourth feedback resource, the thirdcontrol resource, and/or the third data resource may be (pre)configuredor specified. In addition, the third feedback resource, and the fourthfeedback resource may be different in frequency domain. Also, the thirdfeedback resource and the fourth feedback resource may be in the sameTTI or symbol.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of a seconddevice, the device 300 includes a program code 312 stored in the memory310. The CPU 308 could execute program code 312 to enable the seconddevice (i) to receive a third control information on a third controlresource, wherein the third control information schedules or indicates athird data resource, (ii) to receive a third data transmission on thethird data resource, (iii) to determine or derive a third feedbackresource and a fourth feedback resource based on the third controlresource and/or the third data resource, (iv) to receive or decode thethird data transmission successfully, the second device transmits HARQacknowledgement on the third feedback resource, and (v) to not receiveor decode the third data transmission successfully, the second devicetransmits HARQ non-acknowledgement on the fourth feedback resource.Furthermore, the CPU 308 can execute the program code 312 to perform allof the above-described actions and steps or others described herein.

FIG. 17 is a flow chart 1700 according to one exemplary embodiment fromthe perspective of a transmitting device. In step 1705, the transmittingdevice performs sensing on a data resource pool. In step 1710, thetransmitting device selects or derives at least a first data resourcefrom the data resource pool based on the sensing result of the dataresource pool. In step 1715, the transmitting device transmits a firstcontrol information on a first control resource, wherein the firstcontrol information allocates or indicates the first data resource. Instep 1720, the transmitting device performs a first data transmission onthe first data resource. In step 1725, the transmitting device receivesa first feedback transmission associated to the first data transmissionon a first feedback resource, wherein the first feedback resource isassociated with the first control resource and/or the first dataresource.

In one embodiment, the transmitting device may not perform sensing on afeedback resource pool, wherein the feedback resource pool comprises thefirst feedback resource. Alternatively, the transmitting device mayperform sensing on a feedback resource pool, wherein the feedbackresource pool comprises the first feedback resource.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of atransmitting device, the device 300 includes a program code 312 storedin the memory 310. The CPU 308 could execute program code 312 to enablethe transmitting device (i) to perform sensing on a data resource pool,(ii) to select or derive at least a first data resource from the dataresource pool based on the sensing result of the data resource pool,(iii) to transmit a first control information on a first controlresource, wherein the first control information allocates or indicatesthe first data resource, (iv) to perform a first data transmission onthe first data resource, and (v) to receive a first feedbacktransmission associated to the first data transmission on a firstfeedback resource, wherein the first feedback resource is associatedwith the first control resource and/or the first data resource.Furthermore, the CPU 308 can execute the program code 312 to perform allof the above-described actions and steps or others described herein.

FIG. 18 is a flow chart 1800 according to one exemplary embodiment fromthe perspective of a receiving device. In step 1805, the receivingdevice receives a first control information on a first control resource,wherein the first control information allocates or indicates a firstdata resource. In step 1810, the receiving device receives a first datatransmission on a first data resource. In step 1815, the receivingdevice derives a first feedback resource based on the first dataresource and/or the first control resource. In step 1820, the receivingdevice transmits a first feedback transmission associated to the firstdata transmission on the first feedback resource.

In one embodiment, the receiving device may not perform sensing on afeedback resource pool, wherein the feedback resource pool comprises thefirst feedback resource. The first feedback transmission may be setbased on whether the first data transmission is decoded successfully ornot.

In one embodiment, if the receiving device decodes the first datatransmission successfully, the first feedback transmission could deliverpositive acknowledgment. Furthermore, if the receiving device does notdecode the first data transmission successfully, the first feedbacktransmission could deliver non-positive acknowledgment.

In one embodiment, if the receiving device decodes the first datatransmission successfully, the first feedback transmission could deliveran ACK. Furthermore, if the receiving device does not decode the firstdata transmission successfully, the first feedback transmission coulddeliver a NACK.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of areceiving device, the device 300 includes a program code 312 stored inthe memory 310. The CPU 308 could execute program code 312 to enable thereceiving device (i) to receive a first control information on a firstcontrol resource, wherein the first control information allocates orindicates a first data resource, (ii) to receive a first datatransmission on a first data resource, (iii) to derive a first feedbackresource based on the first data resource and/or the first controlresource, and (iv) to transmit a first feedback transmission associatedto the first data transmission on the first feedback resource.Furthermore, the CPU 308 can execute the program code 312 to perform allof the above-described actions and steps or others described herein.

FIG. 19 is a flow chart 1900 according to one exemplary embodiment fromthe perspective of a communication device. In step 1905, the deviceperforms sensing on a data resource pool. In step 1910, the deviceselects or derives at least a first data resource from the data resourcepool based on the sensing result of the data resource pool. In step1915, the device transmits a first control information on a firstcontrol resource, wherein the first control information allocates orindicates the first data resource. In step 1920, the device performs afirst data transmission on the first data resource. In step 1925, thedevice receives a first feedback transmission associated to the firstdata transmission on a first feedback resource, wherein the firstfeedback resource is associated with the first control resource and/orthe first data resource. In step 1930, the device receives a secondcontrol information on a second control resource, wherein the secondcontrol information allocates or indicates a second data resource. Instep 1935, the device receives a second data transmission on the seconddata resource. In step 1940, the device derives a second feedbackresource based on the second control resource and/or the second dataresource. In step 1945, the device transmits a second feedbacktransmission associated to the second data transmission on the secondfeedback resource.

In one embodiment, the device may not perform sensing on a feedbackresource pool. Alternatively, the device may perform sensing on afeedback resource pool for the first feedback resource, and the devicemay not perform sensing on the feedback resource pool for the secondfeedback resource. The feedback resource pool may comprise the firstfeedback resource and the second feedback resource. The data resourcepool may comprise the first data resource and the second data resource.The second feedback transmission may be set based on whether the seconddata transmission is decoded successfully or not.

In one embodiment, if the device decodes the second data transmissionsuccessfully, the second feedback transmission could deliver positiveacknowledgment. Furthermore, if the device does not decode the seconddata transmission successfully, the second feedback transmission coulddeliver non-positive acknowledgment.

In one embodiment, if the device decodes the second data transmissionsuccessfully, the second feedback transmission could deliver an ACK.Furthermore, if the device does not decode the second data transmissionsuccessfully, the second feedback transmission could deliver a NACK.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of acommunication device, the device 300 includes a program code 312 storedin the memory 310. The CPU 308 could execute program code 312 to enablethe communication device (i) to perform sensing on a data resource pool,(ii) to select or derive at least a first data resource from the dataresource pool based on the sensing result of the data resource pool,(iii) to transmit a first control information on a first controlresource, wherein the first control information allocates or indicatesthe first data resource, (iv) to perform a first data transmission onthe first data resource, (v) to receive a first feedback transmissionassociated to the first data transmission on a first feedback resource,wherein the first feedback resource is associated with the first controlresource and/or the first data resource, (vi) to receive a secondcontrol information on a second control resource, wherein the secondcontrol information allocates or indicates a second data resource, (vii)to receives a second data transmission on the second data resource,(viii) to derive a second feedback resource based on the second controlresource and/or the second data resource, and (ix) to transmit a secondfeedback transmission associated to the second data transmission on thesecond feedback resource. Furthermore, the CPU 308 can execute theprogram code 312 to perform all of the above-described actions and stepsor others described herein.

In the context of the embodiments illustrated in FIGS. 17-19 anddescribed above, in one embodiment, the first feedback resource couldhave a fixed or configured or specified time difference, in TTI units,from the first control resource. Furthermore, the first feedbackresource could have a fixed or configured or specified frequencyresource (index) difference, in unit of frequency resource unit, fromthe first control resource. In addition, the first feedback resourcecould have a fixed or configured or specified frequency resource (index)difference, in unit of frequency resource unit, from the first dataresource.

In one embodiment, the index of the first feedback resource could be afixed or configured or specified resource (index) difference from anindex of the first control resource. Furthermore, the index of the firstfeedback resource could be a fixed or configured or specified resource(index) difference from an index of the first data resource.

In one embodiment, the second feedback resource could be a fixed orconfigured or specified time difference, in TTI units, from the secondcontrol resource. Furthermore, the second feedback resource could be afixed or configured or specified time difference, in TTI units, from thesecond data resource. In addition, the second feedback resource could bea fixed or configured or specified frequency resource (index)difference, in frequency resource units, from the second controlresource. Also, the second feedback resource could be a fixed orconfigured or specified frequency resource (index) difference, infrequency resource units, from the second data resource.

In one embodiment, an index of the second feedback resource could be afixed or configured or specified resource (index) difference from anindex of the second control resource. Furthermore, an index of thesecond feedback resource could be a fixed or configured or specifiedresource (index) difference from an index of the second data resource.

In one embodiment, the first data transmission could be a unicasttransmission, a multi-cast transmission, a groupcast transmission, or abroadcast transmission. Furthermore, the second data transmission couldbe a unicast transmission, a multi-cast transmission, a groupcasttransmission, or a broadcast transmission.

FIG. 20 is a flow chart 2000 according to one exemplary embodiment fromthe perspective of a transmitting device. In step 2005, the transmittingdevice performs sensing on a data resource pool. In step 2010, thetransmitting device selects or derives at least a first data resourcefrom the data resource pool based on the sensing result of the dataresource pool. In step 2015, the transmitting device performs sensing ona feedback resource pool. In step 2020, the transmitting device selectsor derives at least a first feedback resource from the feedback resourcepool based on the sensing result of the feedback resource pool. In step2025, the transmitting device transmits a first control information on afirst control resource, wherein the first control information allocatesor indicates the first data resource and the first feedback resource. Instep 2030, the transmitting device performs a first data transmission onthe first data resource. In step 2035, the transmitting device receivesa first feedback transmission associated to the first data transmissionon the first feedback resource.

In one embodiment, the transmitting device could perform sensing on acandidate set of feedback resources, wherein the candidate set offeedback resources comprises the first feedback resource.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of atransmitting device, the device 300 includes a program code 312 storedin the memory 310. The CPU 308 could execute program code 312 to enablethe transmitting device (i) to perform sensing on a data resource pool,(ii) to select or derive at least a first data resource from the dataresource pool based on the sensing result of the data resource pool,(iii) to perform sensing on a feedback resource pool, (iv) to select orderive at least a first feedback resource from the feedback resourcepool based on the sensing result of the feedback resource pool, (v) totransmit a first control information on a first control resource,wherein the first control information allocates or indicates the firstdata resource and the first feedback resource, (vi) to perform a firstdata transmission on the first data resource, and (vii) to receive afirst feedback transmission associated to the first data transmission onthe first feedback resource. Furthermore, the CPU 308 can execute theprogram code 312 to perform all of the above-described actions and stepsor others described herein.

FIG. 21 is a flow chart 2100 according to one exemplary embodiment fromthe perspective of a receiving device. In step 2105, the receivingdevice receives a first control information on a first control resource,wherein the first control information allocates or indicates a firstdata resource and a first feedback resource. In step 2110, the receivingdevice receives a first data transmission on the first data resource. Instep 2115, the receiving device transmits a first feedback transmissionassociated to the first data transmission on the first feedbackresource.

In one embodiment, the receiving device may not perform sensing on afeedback resource pool, wherein the feedback resource pool comprises thefirst feedback resource. The first feedback transmission could be setbased on whether the first data transmission is decoded successfully ornot.

In one embodiment, if the receiving device decodes the first datatransmission successfully, the first feedback transmission could deliverpositive acknowledgment. Furthermore, if the receiving device does notdecode the first data transmission successfully, the first feedbacktransmission could deliver non-positive acknowledgment.

In one embodiment, if the receiving device decodes the first datatransmission successfully, the first feedback transmission could deliveran ACK. Furthermore, if the receiving device does not decode the firstdata transmission successfully, the first feedback transmission coulddeliver a NACK.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of areceiving device, the device 300 includes a program code 312 stored inthe memory 310. The CPU 308 could execute program code 312 to enable thereceiving device (i) to receive a first control information on a firstcontrol resource, wherein the first control information allocates orindicates a first data resource and a first feedback resource, (ii) toreceive a first data transmission on the first data resource, and (iii)to transmit a first feedback transmission associated to the first datatransmission on the first feedback resource. Furthermore, the CPU 308can execute the program code 312 to perform all of the above-describedactions and steps or others described herein.

FIG. 22 is a flow chart 2200 according to one exemplary embodiment fromthe perspective of a communication device. In step 2205, the deviceperforms sensing on a data resource pool. In step 2210, the deviceselects or derives at least a first data resource from the data resourcepool based on the sensing result of the data resource pool. In step2215, the device performs sensing on a feedback resource pool. In step2220, the device selects or derives at least a first feedback resourcefrom the feedback resource pool based on the sensing result of thefeedback resource pool. In step 2225, the device transmits a firstcontrol information on a first control resource, wherein the firstcontrol information schedules or indicates the first data resource andthe first feedback resource. In step 2230, the device performs a firstdata transmission on the first data resource. In step 2235, the devicereceives a first feedback transmission associated to the first datatransmission on the first feedback resource. In step 2240, the devicereceives a second control information on a second control resource,wherein the second control information schedules or indicates a seconddata resource and a second feedback resource. In step 2245, the devicereceives a second data transmission on the second data resource. In step2250, the device transmits a second feedback transmission associated tothe second data transmission on the second feedback resource.

In one embodiment, the device may not perform sensing on the feedbackresource pool for the second feedback resource. Furthermore, the devicemay perform sensing on a candidate set of feedback resources for thefirst feedback resource, wherein the candidate set of feedback resourcescomprises the first feedback resource. The feedback resource pool maycomprise the first feedback resource and the second feedback resource.The data resource pool may comprise the first data resource and thesecond data resource. The second feedback transmission could be setbased on whether the second data transmission is decoded successfully ornot.

In one embodiment, if the device decodes the second data transmissionsuccessfully, the second feedback transmission could deliver positiveacknowledgment. Furthermore, if the device does not decode the seconddata transmission successfully, the second feedback transmission coulddeliver non-positive acknowledgment.

In one embodiment, if the device decodes the second data transmissionsuccessfully, the second feedback transmission could deliver an ACK.Furthermore, if the device does not decode the second data transmissionsuccessfully, the second feedback transmission could deliver a NACK.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of acommunication device, the device 300 includes a program code 312 storedin the memory 310. The CPU 308 could execute program code 312 to enablethe communication device (i) to perform sensing on a data resource pool,(ii) to select or derive at least a first data resource from the dataresource pool based on the sensing result of the data resource pool,(iii) to perform sensing on a feedback resource pool, (iv) to select orderive at least a first feedback resource from the feedback resourcepool based on the sensing result of the feedback resource pool, (v) totransmit a first control information on a first control resource,wherein the first control information schedules or indicates the firstdata resource and the first feedback resource, (vi) to perform a firstdata transmission on the first data resource, (vii) to receive a firstfeedback transmission associated to the first data transmission on thefirst feedback resource, (viii) to receive a second control informationon a second control resource, wherein the second control informationschedules or indicates a second data resource and a second feedbackresource, (ix) to receive a second data transmission on the second dataresource, and (x) to receive a second control information on a secondcontrol resource, wherein the second control information schedules orindicates a second data resource and a second feedback resource.Furthermore, the CPU 308 can execute the program code 312 to perform allof the above-described actions and steps or others described herein.

In the context of the embodiments illustrated in FIGS. 20-22 anddescribed above, in one embodiment, the first feedback resource couldhave an indicated time difference, in TTI units, from the first controlresource, wherein the first control information indicates the timedifference. Furthermore, the first feedback resource could have anindicated time difference, in TTI units, from the first data resource,wherein the first control information indicates the time difference. Inaddition, the first feedback resource could have an indicated frequencyresource (index) difference, in frequency resource units, from the firstcontrol resource, wherein the first control information indicates thefrequency resource (index) difference. Also, the first feedback resourcecould have an indicated frequency resource (index) difference, infrequency resource units, from the first data resource, wherein thefirst control information indicates the frequency resource (index)difference.

In one embodiment, an index of the first feedback resource could have anindicated resource (index) difference from an index of the first controlresource, wherein the first control information indicates the resource(index) difference. Furthermore, an index of the first feedback resourcecould have an indicated resource (index) difference from an index of thefirst data resource, wherein the first control information indicates theresource (index) difference. The first control information couldindicate the resource (index) of first feedback resource.

In one embodiment, the second feedback resource could have an indicatedtime difference, in TTI units, from the second control resource, whereinthe second control information indicates the time difference.Furthermore, the second feedback resource could have an indicated timedifference, in TTI units, from the second data resource, wherein thesecond control information indicates the time difference. In addition,the second feedback resource could have an indicated frequency resource(index) difference, in frequency resource units, from the second controlresource, wherein the second control information indicates the frequencyresource (index) difference. Also, the second feedback resource couldhave an indicated frequency resource (index) difference, in frequencyresource units, from the second data resource, wherein the secondcontrol information indicates the frequency resource (index) difference.

In one embodiment, an index of the second feedback resource could havean indicated resource (index) difference from an index of the secondcontrol resource, wherein the second control information indicates theresource (index) difference. Furthermore, an index of the secondfeedback resource could have an indicated resource (index) differencefrom an index of the second data resource, wherein the second controlinformation indicates the resource (index) difference. The secondcontrol information could indicate the resource (index) of secondfeedback resource.

In one embodiment, the first data transmission could be a unicasttransmission, a multi-cast transmission, a groupcast transmission, and abroadcast transmission. Furthermore, the second data transmission couldbe a unicast transmission, a multi-cast transmission, a groupcasttransmission, and a broadcast transmission.

FIG. 23 is a flow chart 2300 according to one exemplary embodiment fromthe perspective of a transmitting device. In step 2305, the transmittingdevice transmits a third control information on a third controlresource, wherein the third control information schedules or indicates athird data resource. In step 2310, the transmitting device performs athird data transmission on the third data resource. In step 2315, thetransmitting device monitors or detects a third feedback resource and afourth feedback resource, wherein the third feedback resource and thefourth feedback resource are associated to the third control resourceand/or the third data resource.

In one embodiment, if the transmitting device detects or receives athird feedback transmission on the third feedback resource, thetransmitting device could consider the third data transmission isreceived successfully by a first receiving device. Furthermore, if thetransmitting device detects or receives a fourth feedback transmissionon the fourth feedback resource, the transmitting device could considerthe third data transmission is not received successfully by a secondreceiving device.

In one embodiment, the transmitting device may not perform sensing on afeedback resource pool, wherein the feedback resource pool comprises thethird feedback resource and the fourth feedback resource.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of atransmitting device, the device 300 includes a program code 312 storedin the memory 310. The CPU 308 could execute program code 312 to enablethe transmitting device (i) to transmit a third control information on athird control resource, wherein the third control information schedulesor indicates a third data resource, (ii) to perform a third datatransmission on the third data resource, and (iii) to monitor or detecta third feedback resource and a fourth feedback resource, wherein thethird feedback resource and the fourth feedback resource are associatedto the third control resource and/or the third data resource.Furthermore, the CPU 308 can execute the program code 312 to perform allof the above-described actions and steps or others described herein.

FIG. 24 is a flow chart 2400 according to one exemplary embodiment fromthe perspective of a receiving device. In step 2405, the receivingdevice receives a third control information on a third control resource,wherein the third control information schedules or indicates a thirddata resource. In step 2410, the receiving device receives a third datatransmission on the third data resource. In step 2415, the receivingdevice derives a third feedback resource and a fourth feedback resourcebased on the third control resource and/or the third data resource. Instep 2420, if the receiving device receives or decodes the third datatransmission successfully, the receiving device transmits a thirdfeedback transmission on the third feedback resource. In step 2425, ifthe receiving device does not receive or decode the third datatransmission successfully, the receiving device transmits a fourthfeedback transmission on the fourth feedback resource.

In one embodiment, the receiving device may not perform sensing on afeedback resource pool, wherein the feedback resource pool comprises thethird feedback resource and the fourth feedback resource.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of areceiving device, the device 300 includes a program code 312 stored inthe memory 310. The CPU 308 could execute program code 312 to enable thereceiving device (i) to receive a third control information on a thirdcontrol resource, wherein the third control information schedules orindicates a third data resource, (ii) to receive a third controlinformation on a third control resource, wherein the third controlinformation schedules or indicates a third data resource, (iii) toderive a third feedback resource and a fourth feedback resource based onthe third control resource and/or the third data resource, (iv) toreceive or decode the third data transmission successfully, thereceiving device transmits a third feedback transmission on the thirdfeedback resource, and (v) to not receive or decode the third datatransmission successfully, the receiving device transmits a fourthfeedback transmission on the fourth feedback resource. Furthermore, theCPU 308 can execute the program code 312 to perform all of theabove-described actions and steps or others described herein.

In the context of the embodiments illustrated in FIGS. 23-24 anddescribed above, in one embodiment, the third feedback resource couldhave a fixed or configured or specified time difference, in TTI units,from the third control resource. Furthermore, the third feedbackresource could have a fixed or configured or specified time difference,in TTI units, from the third data resource. In addition, the thirdfeedback resource could have a fixed or configured or specifiedfrequency resource (index) difference, in frequency resource units, fromthe third control resource. Also, the third feedback resource could havea fixed or configured or specified frequency resource (index)difference, in frequency resource units, from the third data resource.

In one embodiment, an index of the third feedback resource could have afixed or configured or specified resource (index) difference from anindex of the third control resource. Furthermore, an index of the thirdfeedback resource could have a fixed or configured or specified resource(index) difference from an index of the third data resource.

In one embodiment, the third feedback resource could have an indicatedtime difference, in TTI units, from the third control resource, whereinthe third control information indicates the time difference.Furthermore, the third feedback resource could have an indicated timedifference, in TTI units, from the third data resource, wherein thethird control information indicates the time difference. In addition,the third feedback resource could have an indicated frequency resource(index) difference, in frequency resource units, from the third controlresource, wherein the third control information indicates the frequencyresource (index) difference. Also, the third feedback resource couldhave an indicated frequency resource (index) difference, in frequencyresource units, from the third data resource, wherein the third controlinformation indicates the frequency resource (index) difference.

In one embodiment, an index of the third feedback resource could have anindicated resource (index) difference from an index of the third controlresource, wherein the third control information indicates the resource(index) difference. Furthermore, an index of the third feedback resourcecould have an indicated resource (index) difference from an index of thethird data resource, wherein the third control information indicates theresource (index) difference. The third control information couldindicate the resource (index) of third feedback resource.

In one embodiment, the fourth feedback resource could have a fixed orconfigured or specified time difference, in TTI units, from the thirdcontrol resource. Furthermore, the fourth feedback resource could have afixed or configured or specified time difference, in TTI units, from thethird data resource. In addition, the fourth feedback resource couldhave a fixed or configured or specified frequency resource (index)difference, in frequency resource units, from the third controlresource. Also, the fourth feedback resource could have a fixed orconfigured or specified frequency resource (index) difference, infrequency resource units, from the third data resource.

In one embodiment, an index of the fourth feedback resource could have afixed or configured or specified resource (index) difference from anindex of the third control resource. Furthermore, an index of the fourthfeedback resource could have a fixed or configured or specified resource(index) difference from an index of the third data resource.

In one embodiment, the fourth feedback resource could have an indicatedtime difference, in TTI units, from the third control resource, whereinthe third control information indicates the time difference.Furthermore, the fourth feedback resource could have an indicated timedifference, in TTI units, from the third data resource, wherein thethird control information indicates the time difference. In addition,the fourth feedback resource could have an indicated frequency resource(index) difference, in frequency resource units, from the third controlresource, wherein the third control information indicates the frequencyresource (index) difference. Also, the fourth feedback resource couldhave an indicated frequency resource (index) difference, in frequencyresource units, from the third data resource, wherein the third controlinformation indicates the frequency resource (index) difference.

In one embodiment, an index of the fourth feedback resource could havean indicated resource (index) difference from an index of the thirdcontrol resource, wherein the third control information indicates theresource (index) difference. Furthermore, an index of the fourthfeedback resource could have an indicated resource (index) differencefrom an index of the third data resource, wherein the third controlinformation indicates the resource (index) difference. The third controlinformation could indicate the resource (index) of fourth feedbackresource.

In one embodiment, the third data transmission could be a unicasttransmission, a multi-cast transmission, a groupcast transmission, or abroadcast transmission.

FIG. 25 is a flow chart 2500 according to one exemplary embodiment fromthe perspective of a transmitting device. In step 2505, the transmittingdevice transmits a fourth control information on a fourth controlresource, wherein the fourth control information schedules or indicatesa fourth data resource. In step 2510, the transmitting device performs afourth data transmission on the fourth data resource. In step 2515, thetransmitting device receives a set of feedback transmissions associatedto the fourth data transmission on a set of the multiple feedbackresources, wherein the set of feedback resources are associated to thefourth control resource and/or the fourth data resource.

In one embodiment, the transmitting device may not perform sensing on afeedback resource pool, wherein the feedback resource pool comprises theset of feedback resource. Alternatively, the transmitting device couldperform sensing on a feedback resource pool, wherein the feedbackresource pool comprises the set of feedback resource. A feedbacktransmission on one of the feedback resources could deliver feedbackinformation of one receiving device.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of atransmitting device, the device 300 includes a program code 312 storedin the memory 310. The CPU 308 could execute program code 312 to enablethe transmitting device (i) to transmit a fourth control information ona fourth control resource, wherein the fourth control informationschedules or indicates a fourth data resource, (ii) to perform a fourthdata transmission on the fourth data resource, and (iii) to receive aset of feedback transmissions associated to the fourth data transmissionon a set of the multiple feedback resources, wherein the set of feedbackresources are associated to the fourth control resource and/or thefourth data resource. Furthermore, the CPU 308 can execute the programcode 312 to perform all of the above-described actions and steps orothers described herein.

FIG. 26 is a flow chart 2600 according to one exemplary embodiment fromthe perspective of a receiving device. In step 2605, the receivingdevice receives a fourth control information on a fourth controlresource, wherein the fourth control information schedules or indicatesa fourth data resource. In step 2610, the receiving device receives afourth data transmission on the fourth data resource. In step 2615, thereceiving device derives a fifth feedback resource based on the fourthcontrol resource, the fourth data resource, and/or an identity of thereceiving device. In step 2620, the receiving device transmits afeedback transmission associated to the fourth data transmission on thefifth feedback resource.

In one embodiment, the receiving device may not perform sensing on afeedback resource pool, wherein the feedback resource pool comprises thefifth feedback resource. The feedback transmission could be set based onwhether the fourth data transmission is decoded successfully or not.

In one embodiment, if the receiving device decodes the fourth datatransmission successfully, the feedback transmission could deliverpositive acknowledgment. Furthermore, if the receiving device does notdecode the fourth data transmission successfully, the feedbacktransmission could deliver non-positive acknowledgment.

In one embodiment, if the receiving device decodes the fourth datatransmission successfully, the feedback transmission could deliver anACK. If the receiving device does not decode the fourth datatransmission successfully, the feedback transmission could deliver aNACK.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of areceiving device, the device 300 includes a program code 312 stored inthe memory 310. The CPU 308 could execute program code 312 to enable thereceiving device (i) to receive a fourth control information on a fourthcontrol resource, wherein the fourth control information schedules orindicates a fourth data resource, (ii) to receive a fourth datatransmission on the fourth data resource, (iii) to derive a fifthfeedback resource based on the fourth control resource, the fourth dataresource, and/or an identity of the receiving device, and (iv) totransmit a feedback transmission associated to the fourth datatransmission on the fifth feedback resource. Furthermore, the CPU 308can execute the program code 312 to perform all of the above-describedactions and steps or others described herein.

FIG. 27 is a flow chart 2700 according to one exemplary embodiment fromthe perspective of a communication device. In step 2705, the devicetransmits a fourth control information on a fourth control resource,wherein the fourth control information schedules or indicates a fourthdata resource. In step 2710, the device performs a fourth datatransmission on the fourth data resource. In step 2715, the devicereceives a set of feedback transmissions associated to the fourth datatransmission on a set of the multiple feedback resources, wherein theset of feedback resources are associated to the fourth control resourceand/or the fourth data resource. In step 2720, the device receives afifth control information on a fifth control resource, wherein the fifthcontrol information schedules or indicates a fifth data resource. Instep 2725, the device receives a fifth data transmission on the fifthdata resource. In step 2730, the device derives a fifth feedbackresource based on the fifth control resource and/or the fifth dataresource and/or an identity of the device. In step 2735, the devicetransmits a feedback transmission associated to the fifth datatransmission on the fifth feedback resource.

In one embodiment, the device may not perform sensing on a feedbackresource pool. However, the device may perform sensing on a feedbackresource pool for the set of feedback resources. The device may notperform sensing on the feedback resource pool for the fifth feedbackresource. The feedback resource pool may comprise the fifth feedbackresource. The device may perform sensing on a data resource pool. Thedata resource pool may comprise the fourth data resource and the fifthdata resource. The feedback transmission could be set based on whetherthe fifth data transmission is decoded successfully or not.

In one embodiment, if the device decodes the fifth data transmissionsuccessfully, the feedback transmission on the fifth feedback resourcecould deliver positive acknowledgment. Furthermore, if the device doesnot decode the fifth data transmission successfully, the feedbacktransmission on the fifth feedback resource could deliver non-positiveacknowledgment.

In one embodiment, if the device decodes the fifth data transmissionsuccessfully, the feedback transmission on the fifth feedback resourcecould deliver an ACK. If the device does not decode the fifth datatransmission successfully, the feedback transmission on the fifthfeedback resource could deliver a NACK.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of acommunication device, the device 300 includes a program code 312 storedin the memory 310. The CPU 308 could execute program code 312 to enablethe communication device (i) to transmit a fourth control information ona fourth control resource, wherein the fourth control informationschedules or indicates a fourth data resource, (ii) to perform a fourthdata transmission on the fourth data resource, (iii) to receive a set offeedback transmissions associated to the fourth data transmission on aset of the multiple feedback resources, wherein the set of feedbackresources are associated to the fourth control resource and/or thefourth data resource, (iv) to receive a fifth control information on afifth control resource, wherein the fifth control information schedulesor indicates a fifth data resource, (v) to receive a fifth datatransmission on the fifth data resource, (vi) to derive a fifth feedbackresource based on the fifth control resource, the fifth data resource,and/or an identity of the device, and (vii) to transmit a feedbacktransmission associated to the fifth data transmission on the fifthfeedback resource. Furthermore, the CPU 308 can execute the program code312 to perform all of the above-described actions and steps or othersdescribed herein.

In the context of the embodiments illustrated in FIGS. 25-27 anddescribed above, in one embodiment, the set of feedback resources couldhave fixed or configured or specified time difference(s), in TTI units,from the fourth control resource. Furthermore, the set of feedbackresources could have fixed or configured or specified timedifference(s), in TTI units, from the fourth data resource. In addition,the set of feedback resources could have fixed or configured orspecified frequency resource (index) difference(s), in frequencyresource units, from the fourth control resource. Also, the set offeedback resources could have fixed or configured or specified frequencyresource (index) difference(s), in frequency resource units, from thefourth data resource.

In one embodiment, indices of the set of feedback resources could havefixed or configured or specified resource (index) difference(s) from anindex of the fourth control resource. Furthermore, indices of the set offeedback resources could have fixed or configured or specified resource(index) difference(s) from an index of the fourth data resource.

In one embodiment, the set of feedback resources could have indicatedtime difference(s), in TTI units, from the fourth control resource,wherein the fourth control information indicates the time difference(s).Furthermore, the set of feedback resources could have indicated timedifference(s), in TTI units, from the fourth data resource, wherein thefourth control information indicates the time difference(s). Inaddition, the set of feedback resources could have indicated frequencyresource (index) difference(s), in frequency resource units, from thefourth control resource, wherein the fourth control informationindicates the frequency resource (index) difference(s). Also, the set offeedback resources could have indicated frequency resource (index)difference(s), in frequency resource units, from the fourth dataresource, wherein the fourth control information indicates the frequencyresource (index) difference(s).

In one embodiment, indices of the set of feedback resources could haveindicated resource (index) difference(s) from an index of the fourthcontrol resource, wherein the fourth control information indicates theresource (index) difference(s). Furthermore, indices of the set offeedback resources could have indicated resource (index) difference froman index of the fourth data resource, wherein the fourth controlinformation indicates the resource (index) difference(s). The fourthcontrol information could indicate the resource (index) of the set offeedback resources.

In one embodiment, the set of feedback resources could have indicatedtime difference(s), in TTI units, from the fourth control resource,wherein the time difference(s) is/are indicated or derived by identitiesof a set of receiving devices. Furthermore, the set of feedbackresources could have indicated time difference(s), in TTI units, fromthe fourth data resource, wherein the time difference(s) is/areindicated or derived by identities of a set of receiving devices. Inaddition, the set of feedback resources could have indicated frequencyresource (index) difference(s), in frequency resource units, from thefourth control resource, wherein the frequency resource (index)difference(s) is/are indicated or derived by identities of a set ofreceiving devices. Also, the set of feedback resources could haveindicated frequency resource (index) difference(s), in frequencyresource units, from the fourth data resource, wherein the frequencyresource (index) difference(s) is/are indicated or derived by identitiesof a set of receiving devices.

In one embodiment, indices of the set of feedback resources could haveindicated resource (index) difference(s) from an index of the fourthcontrol resource, wherein the resource (index) difference(s) is/areindicated or derived by identities of a set of receiving devices.Furthermore, indices of the set of feedback resources could haveindicated resource (index) difference(s) from an index of the fourthdata resource, wherein the resource (index) difference(s) is/areindicated or derived by identities of a set of receiving devices. Theresource (index) of the set of feedback resources is/are indicated orderived by identities of a set of receiving devices.

In one embodiment, the fifth feedback resource could have a fixed orconfigured or specified time difference, in TTI units, from the fourthcontrol resource. Furthermore, the fifth feedback resource could have afixed or configured or specified time difference(s), in TTI units, fromthe fourth data resource. In addition, the fifth feedback resource couldhave a fixed or configured or specified frequency resource (index)difference, in frequency resource units, from the fourth controlresource. Also, the fifth feedback resource could have a fixed orconfigured or specified frequency resource (index) difference, infrequency resource units, from the fourth data resource.

In one embodiment, index of the fifth feedback resource could have afixed or configured or specified resource (index) difference from anindex of the fourth control resource. Furthermore, index of the fifthfeedback resource could have a fixed or configured or specified resource(index) difference from an index of the fourth data resource.

In one embodiment, the fifth feedback resource could have an indicatedtime difference, in TTI units, from the fourth control resource, whereinthe fourth control information indicates the time difference.Furthermore, the fifth feedback resource could have an indicated timedifference, in TTI units, from the fourth data resource, wherein thefourth control information indicates the time difference. In addition,the fifth feedback resource could have an indicated frequency resource(index) difference, in frequency resource units, from the fourth controlresource, wherein the fourth control information indicates the frequencyresource (index) difference. Also, the fifth feedback resource couldhave an indicated frequency resource (index) difference, in frequencyresource units, from the fourth data resource, wherein the fourthcontrol information indicates the frequency resource (index) difference.

In one embodiment, index of the fifth feedback resource could have anindicated resource (index) difference from an index of the fourthcontrol resource, wherein the fourth control information indicates theresource (index) difference. Furthermore, index of the fifth feedbackresource could have an indicated resource (index) difference from anindex of the fourth data resource, wherein the fourth controlinformation indicates the resource (index) difference. The fourthcontrol information could indicate the resource (index) of the fifthfeedback resource.

In one embodiment, the fifth feedback resource could have an indicatedtime difference, in TTI units, from the fourth control resource, whereinthe time difference is indicated or derived by the identity of thedevices. Furthermore, the fifth feedback resource could have anindicated time difference, in TTI units, from the fourth data resource,wherein the time difference is indicated or derived by the identity ofthe device. In addition, the fifth feedback resource could have anindicated frequency resource (index) difference, in frequency resourceunits, from the fourth control resource, wherein the frequency resource(index) difference is indicated or derived by the identity of thedevice. Also, the fifth feedback resource could have an indicatedfrequency resource (index) difference, in frequency resource units, fromthe fourth data resource, wherein the frequency resource (index)difference is indicated/derived by the identity of the device.

In one embodiment, index of the fifth feedback resource could have anindicated resource (index) difference from an index of the fourthcontrol resource, wherein the resource (index) difference is indicatedor derived by the identity of the device. Furthermore, index of thefifth feedback resource could have an indicated resource (index)difference from an index of the fourth data resource, wherein theresource (index) difference is indicated or derived by the identity ofthe device. In addition, the resource (index) of the fifth feedbackresource could be indicated or derived by the identity of the device.

In one embodiment, the fourth data transmission could be a unicasttransmission, a multi-cast transmission, a groupcast transmission, or abroadcast transmission. Furthermore, the fifth data transmission couldbe a unicast transmission, a multi-cast transmission, a groupcasttransmission, and a broadcast transmission.

Various aspects of the disclosure have been described above. It shouldbe apparent that the teachings herein may be embodied in a wide varietyof forms and that any specific structure, function, or both beingdisclosed herein is merely representative. Based on the teachings hereinone skilled in the art should appreciate that an aspect disclosed hereinmay be implemented independently of any other aspects and that two ormore of these aspects may be combined in various ways. For example, anapparatus may be implemented or a method may be practiced using anynumber of the aspects set forth herein. In addition, such an apparatusmay be implemented or such a method may be practiced using otherstructure, functionality, or structure and functionality in addition toor other than one or more of the aspects set forth herein. As an exampleof some of the above concepts, in some aspects concurrent channels maybe established based on pulse repetition frequencies. In some aspectsconcurrent channels may be established based on pulse position oroffsets. In some aspects concurrent channels may be established based ontime hopping sequences. In some aspects concurrent channels may beestablished based on pulse repetition frequencies, pulse positions oroffsets, and time hopping sequences.

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, processors, means, circuits, and algorithmsteps described in connection with the aspects disclosed herein may beimplemented as electronic hardware (e.g., a digital implementation, ananalog implementation, or a combination of the two, which may bedesigned using source coding or some other technique), various forms ofprogram or design code incorporating instructions (which may be referredto herein, for convenience, as “software” or a “software module”), orcombinations of both. To clearly illustrate this interchangeability ofhardware and software, various illustrative components, blocks, modules,circuits, and steps have been described above generally in terms oftheir functionality. Whether such functionality is implemented ashardware or software depends upon the particular application and designconstraints imposed on the overall system. Skilled artisans mayimplement the described functionality in varying ways for eachparticular application, but such implementation decisions should not beinterpreted as causing a departure from the scope of the presentdisclosure.

In addition, the various illustrative logical blocks, modules, andcircuits described in connection with the aspects disclosed herein maybe implemented within or performed by an integrated circuit (“IC”), anaccess terminal, or an access point. The IC may comprise a generalpurpose processor, a digital signal processor (DSP), an applicationspecific integrated circuit (ASIC), a field programmable gate array(FPGA) or other programmable logic device, discrete gate or transistorlogic, discrete hardware components, electrical components, opticalcomponents, mechanical components, or any combination thereof designedto perform the functions described herein, and may execute codes orinstructions that reside within the IC, outside of the IC, or both. Ageneral purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

It is understood that any specific order or hierarchy of steps in anydisclosed process is an example of a sample approach. Based upon designpreferences, it is understood that the specific order or hierarchy ofsteps in the processes may be rearranged while remaining within thescope of the present disclosure. The accompanying method claims presentelements of the various steps in a sample order, and are not meant to belimited to the specific order or hierarchy presented.

The steps of a method or algorithm described in connection with theaspects disclosed herein may be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module (e.g., including executable instructions and relateddata) and other data may reside in a data memory such as RAM memory,flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a harddisk, a removable disk, a CD-ROM, or any other form of computer-readablestorage medium known in the art. A sample storage medium may be coupledto a machine such as, for example, a computer/processor (which may bereferred to herein, for convenience, as a “processor”) such theprocessor can read information (e.g., code) from and write informationto the storage medium. A sample storage medium may be integral to theprocessor. The processor and the storage medium may reside in an ASIC.The ASIC may reside in user equipment. In the alternative, the processorand the storage medium may reside as discrete components in userequipment. Moreover, in some aspects any suitable computer-programproduct may comprise a computer-readable medium comprising codesrelating to one or more of the aspects of the disclosure. In someaspects a computer program product may comprise packaging materials.

While the invention has been described in connection with variousaspects, it will be understood that the invention is capable of furthermodifications. This application is intended to cover any variations,uses or adaptation of the invention following, in general, theprinciples of the invention, and including such departures from thepresent disclosure as come within the known and customary practicewithin the art to which the invention pertains.

1. A method of a first device to perform sidelink transmission andreception, comprising: the first device performs sensing on a dataresource pool; the first device selects or derives at least a first dataresource from the data resource pool based on the sensing result of thedata resource pool; the first device transmits a first controlinformation on a first control resource, wherein the first controlinformation allocates or indicates the first data resource; the firstdevice performs a first data transmission on the first data resource toat least one second device; the first device determines or derives afirst set of feedback resource(s) based on the first control resourceand/or the first data resource; and the first device receives a firstset of feedback transmission(s) on the first set of feedback resource(s)from at least the one second device, wherein the first set of feedbacktransmissions are associated with the first data transmission.
 2. Themethod of claim 1, wherein for determining or deriving the first set offeedback resource(s), the first device does not perform sensing on acandidate set of feedback resources, wherein the candidate set offeedback resources comprises the first set of feedback resource(s); andthe first device determines or derives the first set of feedbackresource(s) from the candidate set of feedback resources without basingon sensing result of the candidate set of feedback resources.
 3. Themethod of claim 1, wherein when the first data transmission is unicasttransmission (to a second device), the first set of feedback resource(s)means a first feedback resource, and the first set of feedbacktransmission(s) means a first feedback transmission.
 4. The method ofclaim 3, wherein the first device determines or derives the firstfeedback resource based on the first control resource, the first dataresource, and/or an identity of the second device.
 5. The method ofclaim 1, wherein when the first data transmission is groupcasttransmission (to a sidelink group comprising at least the seconddevice), one of the first set of feedback transmissions, on one of thefirst set of feedback resources, delivers feedback information from onedevice (within the sidelink group).
 6. The method of claim 5, whereinthe first device determines or derives one of the first set of feedbackresources, based on the first control resource, the first data resource,and/or an identity of one device (within the sidelink group).
 7. Themethod of claim 1, wherein the resource association, in time domainand/or frequency domain, between the first set of feedback resource(s)and the first control resource, and/or the first data resource is(pre)configured or specified.
 8. The method of claim 1, wherein thefirst control information comprises no field for indicating the firstset of feedback resource(s).
 9. The method of claim 1, furthercomprising: the first device receives a second control information on asecond control resource, wherein the second control informationallocates or indicates a second data resource; the first device receivesa second data transmission on the second data resource; the first devicedetermines or derives a second feedback resource based on the secondcontrol resource and/or the second data resource; and the first devicetransmits a second feedback transmission associated to the second datatransmission on the second feedback resource.
 10. The method of claim 9,wherein for determining or deriving the second feedback resource, thefirst device does not perform sensing on a candidate set of feedbackresources, wherein the candidate set of feedback resources comprises thesecond feedback resource; and the first device determines/derives thesecond feedback resource from the candidate set of feedback resourceswithout basing on sensing result of the candidate set of feedbackresources.
 11. The method of claim 9, wherein the resource association,in time domain and/or frequency domain, between the second feedbackresource and the second control resource, and/or the second dataresource is (pre)configured or specified.
 12. The method of claim 9,wherein the second control information comprises no field for indicatingthe second feedback resource.
 13. The method of claim 9, wherein thefirst device determines or derives the second feedback resource based onthe second control resource, the second data resource, and/or anidentity of the first device.
 14. The method of claim 9, wherein thecandidate set of feedback resources comprises the first set of feedbackresource(s) and the second feedback resource; and the data resource poolcomprises the first data resource and the second data resource.
 15. Amethod of a first device to perform sidelink transmission and reception,comprising: the first device transmits a third control information on athird control resource, wherein the third control information schedulesor indicates a third data resource; the first device performs a thirddata transmission on the third data resource; the first devicedetermines or derives a third feedback resource and a fourth feedbackresource based on the third control resource and/or the third dataresource; and the first device detects or receives the third feedbackresource and the fourth feedback resource, wherein the third feedbackresource is utilized for delivering HARQ (Hybrid Automatic RepeatRequest) acknowledgement, and the fourth feedback resource is utilizedfor delivering HARQ non-acknowledgement.
 16. The method of claim 15,wherein the third feedback resource and the fourth feedback resource aredifferent in frequency domain, and/or the third feedback resource andthe fourth feedback resource are in the same TTI (Transmission TimeInterval) or symbol.
 17. The method of claim 15, wherein for determiningor deriving the third feedback resource and the fourth feedbackresource, the first device does not perform sensing on a candidate setof feedback resources, wherein the candidate set of feedback resourcescomprises the third feedback resource and the fourth feedback resource;and the first device determines or derives the third feedback resourceand the fourth feedback resource from the candidate set of feedbackresources without basing on sensing result of the candidate set offeedback resources.
 18. The method of claim 15, wherein the resourceassociation, in time domain and/or frequency domain, between the thirdfeedback resource and the third control resource, and/or the third dataresource is (pre)configured or specified; and the resource association,in time domain and/or frequency domain, between the fourth feedbackresource and the third control resource, and/or the third data resourceis (pre)configured or specified.
 19. A method of a second device toperform sidelink transmission and reception, comprising: the seconddevice receives a third control information on a third control resource,wherein the third control information schedules or indicates a thirddata resource; the second device receives a third data transmission onthe third data resource; the second device determines or derives a thirdfeedback resource and a fourth feedback resource based on the thirdcontrol resource and/or the third data resource; if the second devicereceives or decodes the third data transmission successfully, the seconddevice transmits HARQ (Hybrid Automatic Repeat Request) acknowledgementon the third feedback resource; and if the second device does notreceive or decode the third data transmission successfully, the seconddevice transmits HARQ non-acknowledgement on the fourth feedbackresource.
 20. The method of claim 19, wherein the resource association,in time domain and/or frequency domain, between the third feedbackresource, the third control resource, and/or the third data resource is(pre)configured or specified; and the resource association, in timedomain and/or frequency domain, between the fourth feedback resource,the third control resource, and/or the third data resource is(pre)configured or specified; and/or the third feedback resource, andthe fourth feedback resource are different in frequency domain; and/orthe third feedback resource and the fourth feedback resource are in thesame TTI (Transmission Time Interval) or symbol.